Menu Close

Lesson 31: Using ~는 것 with 이다

Click here for a Workbook to go along with this lesson.

This Lesson is also available in Español, Русский, Français, Português, Deutsch and العربية

Jump to:

Vocabulary
Introduction

Using ~는 것 with 이다

 

Vocabulary

Click on the English word to see information and examples of that word in use. You might not be able to understand all of the grammar within the example sentences, but most of the grammar used will be introduced by the end of Unit 2. Use these sentences to give yourself a feel for how each word can be used, and maybe even to expose yourself to the grammar that you will be learning shortly.

A PDF file neatly presenting these words and extra information can be found here.

Nouns:
미소 = smile

Common Usages:
미소를 짓다 = to smile

Examples:
그 여자의 미소가 예뻐요 = That girl’s smile is pretty
그 학생은 미소를 지을 뿐 아무 말도 하지 않았어요 = That student just smiled and didn’t say anything

배달 = delivery

Common Usages:
무료 배달 = free delivery
배달시키다 = to get something ordered to come to you (for example, a food delivery)

Examples:
배달이 아직 안 왔어요 = The delivery hasn’t arrived/come yet
그 웹사이트로 사면 무료 배달을 받을 수 있어요 = If you buy through that site, you can receive free shipping

반지 = ring

Common Usages:
반지를 끼다 = to put on/wear a ring
반지를 끼고 다니다 = to wear a ring while doing something (walking around)

Examples:
저는 반지를 박스 안에 숨겼어요 = I hid the ring in a box
반지를 사려고 두 달 동안 돈을 안 썼어요 = In order to buy a ring, I didn’t spend money for two months
저는 돈이 없어서 그 반지를 살 수 없어요 = I can’t buy that ring because I don’t have money
네가 설마 여자 친구한테 반지 없이 프러포즈를 했어?  = Surely you didn’t propose to your girlfriend without a ring?

입술 = lips

The pronunciation of this word is closer to “입쑬”

Common Usages:
입술을 깨물다 = to bite one’s lips (to hold something that you want to say back)
입술에 키스하다 = to kiss on the lips

Examples:
그는 제 입술에 자기 입술을 댔어요 = He put his lips against mine
그 여자가 입술에 빨간 립스틱을 진하게 발랐어요 = That girl put a lot of (thickly) red lipstick on her lips

미술 = art

Common Usages:
미술수업 = art class
미술(작)품 = work of art
미술계 = the art world

Examples:
우리 회장은 유럽 미술품을 수집해요 = Our CEO collects European art
우리는 미술 수업 시간 동안 여러 가지의 작품을 만들어요 = We make many different types of works in art class

목걸이 = necklace

The pronunciation of this word is closer to “목꺼리”

Notes: “~걸이” is usually attached to a noun to indicate that it is a rack that you can hang a particular object onto. For example, a “수건걸이” would be some kind of towel rack.
However, the words 목걸이 and 귀걸이 don’t describe the rack that you can hang an object onto. Rather, they describe the objects that are being hung.

Common Usages:
목걸이를 풀다 = to untie/take off a necklace
목걸이를 하다 = to wear a necklace

Examples:
여자가 집에 도착하고 목걸이를 풀었어요 = The girl arrived home and unhooked her necklace
우리 엄마의 목에 빤짝빤짝 목걸이가 항상 걸려 있어요 = There is always a shiny necklace hanging around our mother’s neck

귀걸이 = earrings

Notes: “~걸이” is usually attached to a noun to indicate that it is a rack that you can hang a particular object onto. For example, a “수건걸이” would be some kind of towel rack.
However, the words 목걸이 and 귀걸이 don’t describe the rack that you can hang an object onto. Rather, they describe the objects that are being hung.

The word 귀고리 is also acceptable. “고리” by itself refers to some kind of metal that is bent into a circle (or similar shape). Another example would be 열쇠고리 (a key-chain). In theory, “귀걸이” refers to an earring that is long and dangling and “귀고리” refers to an earring that is in the shape of a hoop. However, the majority of Korean people would not be aware of this.

Common Usages:
귀걸이를 풀다 = to untie/take off an earring
귀걸이를 하다 = to wear an earring

Examples:
계단을 올라가다가 귀걸이가 떨어졌어요 = My earing(s) fell out while walking up the stairs

수영복 = bathing suit

Common Usages:
수영복으로 갈아입다 = to change into a bathing suit
수영복을 입다 = to put on a bathing suit

Examples:
바다에 들어가기 전에 수영복으로 갈아입어야 돼요= before I go in the ocean, I need to change into my bathing suit

간식 = snacks

Common Usages:
간식을 먹다 = to have a snack

Examples:
우리는 각 반을 위해 간식을 준비했어요 = We prepared a snack for each class
피자를 다 먹고 나는 엄마에게 줄 간식을 사서 집에 갔다 = After eating all the pizza, I bought snacks to give to Mom, and went home

목표 = goal

Common Usages:
목표를 달성하다/이루다 = to achieve a goal
목표를 세우다 = to set a goal
목표를 바꾸다 = to change a goal

Examples:
다음 1년 안에 달성하고 싶은 목표가 뭐예요?
= What goal do you want to accomplish within the next year?

삶에 성공하고 싶으면 이룰 수 있는 목표를 세워야 돼요
= In order to succeed in life, you need to set achievable goals

= forest

The pronunciation of this word is closer to “숩”

Idiom:
나무를 보고 숲을 보지 못한다 = To not see the big picture (to look at the trees, but not the forest)

Examples:
토끼가 어두운 숲으로 사라졌어요 = The rabbit disappeared into the dark forest
주말에 아이랑 숲에서 산책했어요 = I went for a walk with the kids in the forest on the weekend

주머니 = pocket

Notes: The word “호주머니” is often used as well

Common Usages:
주머니에 넣다 = to put something in a pocket
주머니에서 꺼내다 = to take something out of one’s pockets

Examples:
돈을 주워서 주머니에 넣었어요 = I found/picked up the money and quickly put it in my pocket
신발끈을 매다가 지갑이 주머니에서 떨어졌어요  = While I was tying me shoelaces, my wallet fell out of my pocket

칠판 = blackboard, chalkboard

Common Usages:
칠판을 치우다 = to erase the blackboard
칠판을 닦다 = to erase/wipe the blackboard
칠판에 쓰다 = to write on the blackboard
칠판이 안 보이다 = to not be able to see the blackboard

Examples:
칠판을 보세요! = Look at the blackboard!
그 문제의 정답을 칠판을 써 줄게요 = I’ll write the answer to that problem on the board
교실이 너무 어두워서 학생들은 칠판을 볼 수 없어요 = The students can’t see the board because the classroom is too dark

딸기 = strawberry

Common Usages:
냉동딸기 = frozen strawberry
생딸기 = fresh strawberry

Examples:
딸기를 갈아서 주스를 직접 만들었어요 = I made juice from blending up strawberries
딸기는 유일하게 씨앗이 바깥에 있는 과일이다 = Strawberries are the only fruit with the seeds on the outside

상추 = lettuce

Common Usages:
양상추 = technically this translates to “western lettuce,” but I would call this “iceberg lettuce”
상추를 씻다 = to wash/rinse lettuce
~를/을 상추에 싸 먹다 = to put/wrap something in lettuce and then eat it (when you eat Korean meat, it is common [and delicious] to put a piece in lettuce [along with other things] and then eat it all together)

Examples:
초록색이 진할수록 상추에 비타민이 많아요 = The darker green a lettuce is, the more vitamins it has
고기를 상추에 싸서 먹으면 제일 맛있어요 = If you wrap your meat in lettuce then eat it, it is the most delicious

공사 = construction

Common Usages:
공사 중 = under construction
공사비 = construction costs
공사장 = construction site

Examples:
공사 때문에 이 길은 막혔습니다 = The road is blocked because of the construction

교시 = class, period

Notes: “Class” has many meanings in English, even when it relates to school. “교시” refers to the block of time (or period) where a student learns a particular subject.

Common Usages:
1교시 = 1st period
2교시 = 2nd period

Examples:
저는 오늘 1교시 수업이 있어요 = I have a class first period today
저는 오늘 2교시에 영어회화 수업이 있어요 = I have an English conversation class today at 2nd period
영어 수업은 4교시로 이동했어요 = English class moved to 4th period

종교 = religion

Common Usages:
종교를 믿다 = to have/believe in a religion

Examples:
종교를 믿는 사람들은 보통 교회를 다녀요 = People who believe in a religion usually go to church
캐나다에 가장 흔한 종교는 천주교이다 = The most common religion in Canada is Catholicism

시청 = city hall

Notes: ~청 attaches to various things related to the government to indicate a particular office. For example:
구청 = district office
교육청 = educational office (ministry of education)

Common Usages:
서울시청 = Seoul City Hall
부산시청 = Busan City Hall

Examples:
시청은 보통 도시 한가운데에 있어요 = City Hall is usually right in the middle of a city
혼인신고를 하고 싶으면 시청에서 신청해야 됩니다 = If you want to register your marriage, you need to apply at City Hall

동갑 = the same age

Notes: The Korean age system is different than most of the world. In Korea, everybody born in a particular year is the same age. While Korean people still celebrate their birthdays, they do not get “older” on that day. Everybody in Korea gets one year older on new year’s day. Therefore, you can use “동갑” with anybody who is born the same year as you.

Examples:
우리는 동갑이야 = We are the same age
너와 동갑인 여자를 만나야 돼 = You need to meet a girl who is your age

긍정적 = positive

Common Usages:
긍정적인 영향 = a positive effect
긍정적인 성격 = a positive personality
긍정적으로 생각하다 = to think positively
긍정적으로 행동하다 = to act positively
긍정적으로 보다 = to see something positively

Examples:
이런 힘든 때에는 긍정적으로 생각하는 것이 아주 중요해요
= In difficult times like this, it is important to think positively

지금부터 저는 저의 삶을 더 긍정적으로 볼 거예요
= From now on I’m going to look at my life more positively

새로운 직장에서 내일은 더 긍정적인 자세로 일을 할 것이다
= At my new workplace, tomorrow, I will work with a more positive frame of mind

부정적 = negative

Common Usages:
부정적인 영향 = a negative effect
부정적인 성격 = a negative personality
부정적으로 생각하다 = to think negatively
부정적으로 행동하다 = to act negatively
부정적으로 보다 = to see something negatively

Examples: 요즘에는 우리 아들이 아주 부정적으로 행동해요
= These days, our son is acting very negatively

우울증에 걸리는 사람들은 부정적인 생각을 많이 해요
= People with depression think a lot of negative thoughts

Verbs:
어울리다= to get along with

Common Usages:
잘 어울리다 = to go well with something, to get along well with somebody

Notes: This word can be used to indicate that people get along, for example:
그들은 잘 어울리지 않을 것 같아요 = They probably won’t get along
그와 잘 어울리려고 얘기를 많이 해요 = In order to get along with him, I talk with him often
제가 그 사람을 싫어하는 게 아니라 우리는 그냥 잘 어울리지 못해요 = It’s not that I don’t like that person, we just don’t get along

It can also be used to indicate that two objects (or one person and one object) go well together:
그 셔츠가 눈 색깔과 잘 어울려요 = That shirt goes well with your eyes
그런 스타일의 머리가 너와 잘 어울려 = That hairstyle suits you well

알리다 = to tell, to inform

Notes: 알다 is used to indicate that the speaker knows something. “Something” acts as the object of the sentence. For example:

저는 그 사람의 이름을 알아요 = I know that person’s name

알리다 is used when one other person tells another person something. In theory, the first person is “letting somebody know.” For example:

부장은 그 회사원에게 오늘 해고됐다고 알렸어요 = The boss told the worker that he was fired today

In the example above, both the “boss” and the “worker” are being referred to, and neither of them would be the listener or the speaker. In these cases, it is acceptable to use 알리다.

However, when talking about a fact that you told somebody, or a fact that somebody told you, you are more likely to see ~아/어주다 attached to 알리다. The grammar behind ~아/어주다 is discussed in Lesson 41. For example:

(만약) 학교에 간다면 저에게 알려주세요 = If you go to school, let me know
이 사실을 부장님께 알려 줘야겠어요 = I guess I should tell the boss (about) that fact
숙제를 다 하거든 알려줘! = Let me know when you are done your homework!
거기에 가면 알려주세요 = If you go there, let me know
그 사실을 저한테 미리 알려줬으면 좋겠어요 = I wish you told that fact to me earlier

아끼다 = to cherish, to save

Notes: The adjective 아깝다 is similar, but it is a descriptive word (an adjective) that describes that something is precious/important and shouldn’t be thrown away because it would be wasteful. For example:

그렇게 하면 돈이 아까워요 = If you do it like that, it is a waste of money
(Money is precious and important, so don’t do it like that because it would be wasteful)

컵이 아까워서 안 버렸어요 = This cup is precious/important, so I didn’t throw it away
(It would be wasteful to throw this cup away, so I didn’t throw it away)

Common Usages:
아껴 쓰다 = to save something
아껴 먹다 = to save something to eat it later

Examples:
특별히 내가 아끼는 립스틱을 발랐다 = I also put on the special lipstick that I was saving
가뭄 때문에 물을 아껴 써야 돼요 = We need to save/conserve water because of the drought

남기다 = to leave something

The passive form of this word is 남다 (to be left)

Common Usages:
남겨 주다 = to leave for somebody
남겨 두다 = to put/leave something
인상을 남기다 = to leave an impression
(the translation for “남겨 두다” isn’t very different from just “남기다.” Technically, the meaning of 남겨 두다 incorporates the meanings of 남기다 (to leave) and 두다 (to put).

Examples:
그 선생님은 우리에 좋은 인상을 남겼어요 = That teacher left a good impression on us
동생을 위해 스파게티를 조금 남겼어요 = I left a little bit of spaghetti for my younger brother/sister

면도하다 = to shave

Notes: The word “밀다” is often used as well

Common Usages:
면도기 = razor

Examples:
저는 이틀에 한 번 면도해야 돼요 = I need to shave once every two days
남자들이 면도를 어떻게 하는지 보통 자기 아버지로부터 고등학교 때 배워요 = Boys usually learn how to shave from their fathers when they are in high school

빌리다 = to borrow, to lend

Notes: 빌리다 is used when the subject of the sentence receives (borrows) something. For example:

저는 친구에게서 돈을 빌렸어요 = I borrowed money from my friend
저는 자동차를 빌릴 거예요 = I will rent a car

However, when the subject of the sentence gives (lends) something, 빌려주다 can be used. The grammar behind ~아/어주다 is discussed in Lesson 41. For example:

저는 친구에게 돈을 빌려줬어요 = I lent my friend money
핸드폰을 잠깐 빌려주세요 = Please lend me your phone for a second

Because 빌리다 and 빌려주다 are technically the same word (빌려주다 is just 빌리다 with ~아/어주다 attached), Korean people often confuse the usages of “borrow” and “lend” in English. You will often hear Korean people say something like “He borrowed me a pen.”

샤워하다 = to shower

Notes: English pronunciation of the word “shower”

Common Usages:
샤워실 = shower room/stall

Examples:
저는 샤워하러 집에 갈 거예요 = I will go to my house to shower
샤워를 매일 할 필요가 없어요 = I/you don’t need to shower every day
샤워를 하면서 노래를 불렀어요 = I sang a song while taking a shower
샤워를 하고 로션을 바르고 화장을 했다 = After showering, I put lotion and makeup on

덮다 = to cover

The pronunciation of this word is closer to “덥따”
The passive form of this word is 덮이다 (to be covered)

Notes: 덮다 and 가리다 have similar meanings, as they are both used when “covering” something.
덮다 is usually used when covering something from above – like a blanket covering a person.
가리다 is usually used when covering something from the side – like a hand covering a face or clothing covering a person’s body.

Common Usages:
책을 덮다 = to close a book

Examples:
저는 구멍을 신문지로 덮었어요 = I covered the hole with newspaper
시험을 시작하자 학생들은 책을 덮었어요 = When the exam started, the students closed their books
저는 이불을 덮었어요 = I covered (myself) with a blanket (This looks awkward to English speakers because the object of the sentence (“이불”) is the thing that is being used to cover something. However, this is how Korean people say it)

없어지다 = to disappear

The pronunciation of this word is closer to “업써지다”

Examples: 돈이 다 없어졌어요! = All the money disappeared!
제가 탁자에 둔 접시가 없어졌어요 = The plate I put on the table disappeared
어렸을 때 큰 충격을 받아 그때의 기억이 없어졌어요 = When I was young I suffered (received) a huge shock, and my memory of that time disappeared

따라가다 = to follow

Notes: 따라가다 is used when you are following somebody/something. Because “가다” is used in the word, you are “going” towards the person/thing.
따라오다 is used when you are being followed by somebody/something. Because “오다” is used in the word, somebody/something is “coming” towards you.

Common Usages:
사람을 따라가다 = to follow a person
안내문을 따라가다 = to follow the information signs
길을 따라가다 = to follow a road
유행을 따라가다 = to follow a trend

Examples:
그 앞에 있는 차를 계속 따라가세요! Keep following the car in front of you!
무서운 집으로 형을 따라갔어요 = I followed my older brother to the scary house

따라오다 = to be followed

Notes: 따라가다 is used when you are following somebody/something. Because “가다” is used in the word, you are “going” towards the person/thing.
따라오다 is used when you are being followed by somebody/something. Because “오다” is used in the word, somebody/something is “coming” towards you.

Common Usages:
사람이 뒤를 따라오다 = a person following behind you/me/somebody

Examples:
저를 따라 오지 마세요 = Don’t follow me
친구들이 다른 차로 우리를 따라오고 있어요 = Friends are following us in another car

지나가다 = to go and pass by

Examples:
이 건물을 지나가서 오른 쪽으로 가세요 = Go past this building, then go right

아들은 아빠를 보고 그를 알아보지 못하는 듯이 그냥 지나갔어요
= He looked at his father and walked past him as if he didn’t recognize him

고속도로에서 발생한 사고에 의해 사람들이 지나가지 못했어요
= Due to the accident (that occurred) on the highway, people couldn’t pass

키우다 = to raise (children), to train (animals), to develop (skills)

Notes: This is actually a verb of the adjective “크다” big. In theory, it means “to make big.” In effect, this verb can often be used interchangeably with “기르다.” The difference between the two is that 기르다 is focused on the “raising/watching/upbringing” of a person/animal/plant, whereas “키우다” is focused on making them “bigger.”

Common Usages:
강아지를 키우다 = to raise a puppy
근육을 키우다 = to build muscles
애기를 키우다 = to raise a baby

Examples:
어렸을 때 강아지를 키우고 싶었어요 = When I was young, I wanted to raise a puppy
아이를 키우면서 학업을 계속하고 싶어요 = I want to continue my studies while I raise my baby

참다 = to hold back, to endure

The pronunciation of this word is closer to “참따”

Common Usages:
재채기를 참다 = to hold a sneeze
눈물을 참다 = to hold/fight back one’s tears
웃음을 참다 = to hold back one’s laughter
고통을 참다 = to endure pain

Examples:
저는 그녀한테 키스하고 싶은 충동을 참지 못했어요 = I couldn’t resist the urge to kiss her
치과의사가 환자에게 고통을 참을 수 있냐고 물어봤어요 = The dentist asked the patient if he/she could endure the pain

선택하다 = to choose

The pronunciation of this word is closer to “선태카다”
The noun form of this word (“선택”) translates to “a choice”

Examples:
제일 편리한 것을 선택해도 돼요 = You may choose the most convenient one
학생들은 교과목 두 개 중에 하나를 선택해야 해요 = Students must choose one out of the two subjects

깨닫다 = to realize

Common Usages:
중요성을 깨닫다  = to realize the importance

Examples:
그 시대가 그렇게 길었는지 깨닫지 못했어요 = I didn’t realize that era was so long

한국 학생들은 영어의 중요성을 깨닫지 못해요
= Korean students don’t realize the importance of English

신랑이 신부를 보면 그녀가 얼마나 예쁜지 깨달을 거예요
= The groom will realize how pretty the bride is when he sees her

그녀가 그 셔츠가 거기에 없는 것을 깨닫지 못할 거기 때문에 저는 그냥 가져갈 거예요
= She won’t notice that shirt is gone (not here) so I’m just going to take it

댓글을 읽다 보니 세상에는 정말 다양한 사람들이 있다는 것을 깨닫게 되었어요
= After reading the comments I came to realize there really are all kinds of people in the world

그는 그때 너무 어렸고 다른 여자들을 만나 본 적이 없었기 때문에 그녀가 좋은 여자라는 사실을 깨닫지 못했었다
= He was too young at that time, and because he didn’t have the experience of meeting other girls, he hadn’t realized that she was a good girl

Passive Verbs:
쓰이다 = to be written on

Translation: to be written on
The active form of this word is 쓰다 (to write)

Examples:
각 자리에 번호가 쓰여 있어요 = There is a number written on each seat
정답이 칠판에 쓰여 있어요 = The right answer is written on the blackboard
편지에 ‘너를 사랑해’라고 쓰여 있어요 = “I love you” is written on the letter

Adjectives:
부럽다 = to be envious

The pronunciation of this word is closer to “부럽따”

Notes: ~아/어하다 is often attached to 부럽다 to form 부러워하다. The grammar for this is introduced in Lesson 105.

Examples:
그 팀이 이겨서 저는 아주 부러웠어요 = I was envious of the other team because they won
농구를 잘하는 사람들이 부러워요 = I’m envious of people who can play basketball well

Adverbs and Other Words:
= a certain way/method

Common Usages:
이런 식으로 하다 = to do in this sort of way
그런 식으로 하다 = to do in that sort of way
저런 식으로 하다 = to do in that sort of way

Examples:
이런 식으로 해 보세요 = Try doing it this way
공을 그런 식으로 던지면 어깨가 언젠가 아플 거예요 = If you throw a ball like that, one day your shoulder will be sore

아까 = earlier

Examples:
저는 아까 컴퓨터를 켰어요 = I turned the computer on earlier
제가 아까 이 탁자에 열쇠를 놓았는데 혹시 열쇠를 가져간 사람을 봤어요? = I put keys on this table earlier. Did you happen to see the person who took them?

= tightly

꽉 잡다 = to hold on tight(ly)

Examples: 손잡이를 꽉 잡으세요 = Please hold on to (the handle) tightly

For help memorizing these words, try using our mobile app.

 

Introduction

I keep saying this, but you have learned a lot about using the ~는 것 principle. Don’t think that you’re out of the woods yet – because there is still a lot to know. In this lesson, you will learn how to use ~는 것 with 이다.
Let’s get started.

 

 

Using ~ with 이다

You’ve learned a lot about how to add ~는 것 to any verb (and technically adjectives as well by using ~ㄴ/은 것), but you have yet to learn about how to add it to 이다.

You are probably asking yourself: When would I ever want to add ~는 것 to 이다?
(I just want to point out that this is actually the same thing as adding ~ㄴ to “~적이다” words, which you learned in Lesson 16.)

Let’s remember what ~는 것 does:

If you want to just say a noun, you can just say a noun. For example:
Person = 사람

If you want to describe that noun, you can use adjectives:
똑똑한 사람 = smart person

Or verbs:
먹고 있는 사람 = the person who is eating

But… now think about this for a second… what if you want to describe a noun with a noun? Look at the difference (or similarities) between the three following sentences:

똑똑한 사람= the smart person (or – person who is smart)
먹고 있는 사람 = the person who is eating
_____________= the person who is a teacher

How would you do that? Remember that 이다 is conjugated as an adjective. Using the ~는 것 principle with 이다 is really no different than adding ~ㄴ/은 to an adjective to describe an upcoming noun. Because 이다 is conjugated as an adjective, the following would not be correct:

선생님이는 남자…

Instead, 이다 gets conjugated as ~인. For example:

[직업이] 선생님인 사람들은 인기가 많아요 = People who[se jobs] are teachers are popular
(It sounds slightly more natural to say “직업이 선생님인 사람들” in this case instead of just “선생님인 사람들.” Remember here that the entire clause before “~인” is describing the upcoming noun. In this case, the clause is “직업이 선생님이다” which would unnaturally translate to something like “the job is a teacher”. However, when put in the place of describing an upcoming noun, it can translate to “직업이 선생님인 사람들 = people whose jobs are teachers”. At any rate, try not to worry about the use of “직업” (as I realize it might be difficult) in that sentence and focus more on the big picture of what adding “~” to 이다 accomplishes. 

The thing is, as you can see with my big blurb above, this may not be as simple as it should be. Most of the time, there would be a better way – using another word or something to accomplish the same sentence. For example, in the sentence above “직업이 선생님인 사람들은 인기가 많아요”, is the meaning not exactly the same (in English) if we just say “Teachers are popular”? For example:

선생님들은 인기가 많아요 = Teachers are popular
Here, we are accomplishing the same thing but don’t need to use 이다 as a descriptor in the sentence.

Another great example would be if you wanted to say something like:

“Students who are girls wear skirts”

That would translate to something like:

여자인 학생들은 치마를 입는다

But, that sentence sounds ridiculous (in both English and Korean). In Korean, it would sound much better if you just used the word “여학생”, which literally means “female students.” For example:

여학생들은 치마를 입는다 = female students wear skirts
(I would much rather say “female students must wear skirts,” but you haven’t learned how to do that yet, and I try not to use examples that use a concept you haven’t learned)

Despite this, there will be some times where you will find the need for using ~는 것 with 이다. Some times this happens when you come across a noun that has the feeling of an adjective. For example, the word “부자” literally means “rich person.” In English, if we wanted to say “that person is rich,” the word “rich” acts as an adjective. However, in Korean, they would say:

그 사람은 부자야 = That person is (a) rich (person)

Here, 부자 acts as a noun, and the whole sentence is predicated by 이다. In this case, you might find it useful to use 이다 + ~ㄴ to describe an upcoming noun. For example:

내 친구는 부자인 아버지를 자랑했어 = My friend boasted about/was showing off his rich father

Another example using the word “불법” which, as a noun, translates to “illegal”:

슬기는 불법인 일을 하고 있어요 = Seulgi is doing something illegal

It is also common to see this form attached to somebody’s job title to describe their name. Sort of like saying “He is Rob, the CEO of Samsung”. For example:

Titanic 배우인 Leonardo Dicaprio는 잘생겼어요 = Leonardo Dicaprio, who is an actor in Titanic is handsome

At this point, you might be saying “all of this sounds really complicated and I can’t even really understand when I would use this form.” I agree with you, this looks complicated. The thing is, the foundation of many other (more complicated) grammatical principles have ~는 것 incorporated within them. These grammatical principles, in addition to being able to attach to verbs and adjectives, are able to attach to 이다 as well.

Here are some other sentences using other grammatical principles that you have not learned yet. I’m including these just so you can see that attaching ~ㄴ to 이다 is important to your Korean studies as you progress:

그 사람은 가난한 사람인 것처럼 행동했어요 = That person acted like a poor person
(처럼 is introduced in Lesson 67)

그는 축구선수인 만큼 달리기를 잘해요 = He runs as well as a soccer athlete/player
(만큼 is introduced in Lesson 72) 

그 사람이 너의 아버지인 줄 몰랐어요 = I didn’t know that person is your father
(줄 is introduced in Lesson 85)

In each case above, ~ㄴ is attached to 이다 to form “인”. You can see in each example that “인” is used to describe an upcoming noun. There are many more examples of how 이다 can be used to describe an upcoming noun like this, but I don’t need to include them all here, as you will learn about them as they become important.

~는지 is also added to 이다 in this same way. Again, because 이다 acts as an adjective ~ㄴ/은 should be added to it (이다 + ㄴ/은지 will always be ~인지). For example:

그 사람이 선생님인지 모르겠어요 = I don’t know if that person is a teacher
그 사람이 선생님인지 아닌지 모르겠어요 = I don’t know if that person is a teacher or not
우리가 동갑인지 몰랐어요 = I didn’t know that we were the same age
이것이 저의 엄마의 목걸인지 어떻게 알아요? = How do you know that this is my mother’s necklace?

Often times 이다 is attached to a question word to predicate a sentence. In this same sense, you will often see ~인지 attached to question words. For example:

Note that the pairs of sentences below are not dialogues. I organized them this way to show you the similar format that you can see between using ~인지 and using 이다 to predicate a sentence.

비상출구가 어디예요? = Where is the emergency exit?
비상출구가 어디인지 모르겠어요 = I don’t know where the emergency exit is

지금 몇 시예요? = What time is it now?
지금 몇 시인지 모르겠어요 = I don’t know what time it is now

당신의 목표가 뭐예요? = What is your goal?
저의 목표가 무엇인지 알아요? = Do you know what my goal is?

이 일의 관리자가 누구예요? = Who is the manager of this job?
이 일의 관리자가 누구인지 알아요? = Do you know who the manager of this job is?

가격이 얼마예요? = How much is this?
가격이 얼마인지 모르겠어요 = I don’t know how much the price is

——————-

It is also possible, as it is with attaching ~는 것 to a verb or ~ㄴ/은 것 to an adjective, to turn an entire clause into a noun, and then predicate the sentence using a verb. Just like how you learned how to write this sentence in Lesson 26:

I am only including the brackets below to show you that we are still using the same basic sentences of subject – object – verb.

저는 (사과)를 원해요 = I want apples
저는 (친구가 사과를 가져오는 것)을 원해요 = I want my friend to bring apples

You can do the same thing but with 이다 here:

내가 (열쇠를 안 가져온 것)을 깨달았어 = I realized that I didn’t bring my keys
내 (행동은 실수인 것)을 깨달았어 = I realized that my actions (what I did) is/was a mistake

That’s it for this lesson!

Okay, I got it! Take me to the next lesson! Or,
Click here for a Workbook to go along with this lesson.