I think / It seems - 하는 거 같애 (General)

I think / It seems - 하는 거 같애/같아 (General)

하는 거 같애 means "I think he/she/they is/are doing (something)" or "It seems he/she/they are doing (something)."
Please note that although grammatically 하는 거 같아 is right. In spoken Korean, it's usually pronounced 하는 거 같애.


[Verbs]

Written Form	Present	Past
Positive	하는 것 같다	했던 것 같다
Negative	하지 않는 것 같다 안하는 것 같다	하지 않았던 것 같다 안했던 것 같다

Spoken Form	Present	Past
Positive	하는 거 같애	했던 거 같애
Negative	하지 않는 거 같애 안하는 거 같애	하지 않았던 거 같애 안했던 거 같애

Note: In written Korean, it is written 하는 것 같다 whereas in spoken Korean, it is spoken as 하는 거 같애. It is mostly likely due to the fact that 것 is a lot more cumbersome to pronounce than 거 when speaking.


Rules
 
1. Take 다 off a plain form of verbs and attach 는 거 같애/지 않는 거 같애 etc. to it.
2. Drop ㄹ off a plain form of verbs that have ㄹ as a final consonant.
3. Take 다 off a past tense form of verbs and attach 던 것 같다/던 거 같애 etc. to it.

• 하다 → 하는 거 같애 = I think they do / It seems they do
• 먹다 → 먹는 거 같애 = I think they eat / It seems they eat
  
• 일어나다 → 일어나는 거 같애 = I think they get up
  
• 자다 → 자는 거 같애 = I think they sleep
  
• 보다 → 보는 거 같애 = I think they watch
  
• 씻다 → 씻는 거 같애 = I think they wash
  
• 달리다 → 달리는 거 같애 = I think they run
  
• 놀다 → 노는 거 같애 = I think they muck around
  
• 살다 → 사는 거 같애 = I think they live
  

• 했다 → 했던 거 같애 = I think they did
  
• 먹었다 → 먹었던 거 같애 = I think they ate
  
• 봤다 → 봤던 거 같애 = I think they watched
  
• 살았다 → 살았던 거 같애 = I think they lived
  
• 놀았다 → 놀았던 거 같애 = I think they mucked around
  

Example Sentences

• 저기서 사람들이 축구 하는 거 같애 = I think people are playing soccer over there.
  
• 이 개는 저 개집에서 살았던 거 같애 = I think this dog lived in that kennel. = I think this dog used to live in that kennel.
• 저 방에는 아기가 자고 있는 거 같애 = I think a baby is sleeping in that room.
• 나는 밥을 빨리 안먹는 거 같애 = I think I don't eat (a meal) fast.

[Adjectives]

Written Form	Present	Past
Positive	좋은 것 같다	좋았던 것 같다
Negative	좋지 않은 것 같다 안좋은 것 같다	좋지 않았던 것 같다 안좋았던 것 같다

Spoken Form	Present	Past
Positive	좋은 거 같애	좋았던 거 같애
Negative	좋지 않은 거 같애 안좋은 거 같애	좋지 않았던 거 같애 안좋았던 거 같애

Rules

1. Attach a descriptive form of adjectives to 거 같애.
2. Take 다 off a past tense form of adjectives and attach 었던 거 같애.

• 좋은 → 좋은 거 같애 = I think it's good / It seems good
• 많은 → 많은거 같애 = I think there's a lot / There seems a lot
  
• 큰 → 큰 거 같애 = I think it's big / It seems big
  
• 작은 → 작은 거 같애 = I think it's small / It seems small
  
• 예쁜 → 예쁜 거 같애 = I think it's pretty / It seems pretty
  
• 똑똑한 → 똑똑한 거 같애 = I think he's clever / He seems clever
  
• 솔직한 → 솔직한 거 같애 = I think she's honest / She seems honest
• 좋았다 → 좋았던 거 같애 = I think it was good / It seemed good
  

• 맛있었다 → 맛있었던 거 같애 = I think it was delicious
  
• 재밌었다 → 재밌었던 거 같애 = I think it was fun
  
• 쉬웠다 → 쉬웠던 거 같애 = I think it was easy
  
• 많았다 → 많았던 거 같애 = I think there was a lot

Example sentences

• 태국음식은 맛있는 거 같애 = I think Thai food is delicious
• 이 집은 굉장히 큰 거 같애 = I think this house is enormously big.
• 이번 수학시험은 정말 쉬웠던 거 같애 = I think the maths test was really easy.
• 내 기억에 저 들 위에는 꽃들이 많았던 거 같애 = According to my memory, I think there were a lot of flowers on that hill.

[Nouns]

Written Form	Present	Past
Positive	고양이인 것 같다	고양이였던 것 같다
Negative	고양이가 아닌 것 같다	고양이가 아니었던 것 같다

Spoken Form	Present	Past
Positive	고양이(인 거) 같애	고양이였던 거 같애
Negative	고양이(가) 아닌 거 같애	고양이(가) 아니었던 거 같애

Note: The object particle, 가/이, is usually omitted in spoken Korean. 인 거 is also usually omitted.

같다's original meaning is "look like." Therefore, 같애 phrases can have alternative translations but essentially they mean the same thing.

• 하는 거 같애 = I think they're doing. It looks like they're doing.
• 예쁜 거 같애 = I think it's pretty. It looks pretty.
  
• 치킨인거 같애 = I think it's a chicken. It looks like a chicken (food).
  

Rules

Attach 인 것 같다/였던 것 같다/인 거 같애/였던 거 같애 to a noun.

• 강아지(인 거) 같애 = I think it's a puppy (It looks like a puppy)
  
• 고양이(인 거) 같애 = I think it's a cat
  
• 뻐꾸기(인 거) 같애 = I think it's a cuckoo
  
• 나무(인 거) 같애 = I think it's a tree
• 사람(인 거) 같애 = I think it's a person
  
• 학교(인 거) 같애 = I think it's a school

Example sentences

• 민희: 너 저 동물이 뭔지 알아? = Do you know what that animal is?
• 수영: 저건 사자 같애. = I think that is a lion. (That looks like a lion)
  
• 민희: 사자 아닌 거 같은데. 호랑이 같애. = I don't think that is a lion. I think it's a tiger.
• 수영: 그런가? 그럼 저 멀리 저건 뭐지? = Is it? Then what is that over there afar? 
• 민희: 사람은 아닌 거 같애. 동물인 거 같애. = I don't think it's a human. I think it's an animal.
  
• 수영: 침팬지다. = It's a chimpanzee.
• 민희: 침팬지 같았어. = I thought that was a chimpanzee. (It looked like a chimpanzee)
  

Note: 같다's past tense is 같았어 and so 고양이 같았어 = I thought it was a cat.


Formal Forms

Rules  

Written Korean = Change 다 to 습니다.
Spoken Korean = Attach 요 to the end of a sentence. 
eg.

• 태국음식은 맛있는 것 같습니다 = I think Thai food is delicious
• 이 집은 굉장히 큰 거 같애요 = I think this house is enormously big.
• 이번 수학시험은 정말 쉬웠던 거 같애요 = I think the maths test was really easy.
• 내 기억에 저 들 위에는 꽃들이 많았던 거 같애요 = According to my memory, I think there were a lot of flowers on that hill.

They/he/she think(s) = ~ 같대

같대 is a shortened form of 같다고 해 and it is used to express what they/he/she think(s). 같대 is usually used in spoken Korean. Attach 요 to 같대 to make it formal.

• 할머니가 이 개는 저 개집에서 살았던 거 같대 = Grandma thinks this dog lived in that kennel. = Grandma thinks this dog used to live in that kennel.
• 엄마가 저 방에는 아기가 자고 있는 거 같대 = Mum thinks a baby is sleeping in that room.
• 친구가 나는 밥을 빨리 먹는 거 같대요 = My friend thinks I eat (a meal) fast.

• 폴이 태국음식은 맛있는 거 같대 = Paul thinks Thai food is delicious
• 동생의 기억엔 저 들 위에는 꽃들이 많았던 거 같대요 = According to my younger (brother/sister)'s memory, He/she thinks there were a lot of flowers on that hill.

• 강아지(인 거) 같대 = They/he/she think(s) it's a puppy (It looks like a puppy)
• 고양이(인 거) 같대요 = They/he/she think(s) it's a cat

Adverbs - 부사

Adverbs - 부사

Adjective	Present	Adverb
Positive	크다	크게
Negative	크지 않다	크지 않게 안크게

Note: 크지 않게 is more commonly used in written Korean while 안크게 is more common in spoken Korean.

Rules

1. Take 다 off an adjective of the present tense and attach 게/지 않게 to it.
2. Attach 안 to a positive form of adverbs to turn it into its negative form.

Written	Present	Adverb
High	높다	높게, 높이
Low	낮다	낮게
Big	크다	크게
Small (size)	작다	작게
Spacious	넓다	넓게
Delicious	맛있다	맛있게
Many	많다	많게, 많이
Small (quantity)	적다	적게
Kind	착하다	착하게
Fast	빠르다	빠르게, 빨리
Slow	느리다	느리게
Handsome	멋있다	멋있게

Note:

Adverbs come just before verbs to describe actions.

많다, 빠르다 and 높다 each have two adverbial forms. 많이, 빨리 and 높이 are more commonly used than 많게, 빠르게 and 높게.

Example sentences

• 나는 스테이크를 맛있게 먹었다 = I ate my steak "deliciously" (Lit. I enjoyed my steak)
• 거북이는 느리게 걷는다 = A tortoise walks slowly
• 밥을 많이 먹었다 = I ate a big meal. (Lit. I ate a meal a lot.)
• 집에 빨리 가자! = Let's go home quickly!
• 철수는 결승점까지 빨리 달렸다. = Cheol-su ran fast to the finish line.
• 성우는 케이크를 크게 만들었다 = Seong-u made a large cake. (Lit. Seong-u made his cake big.)
• 높이 나는 새가 멀리 본다 = The higher a bird flies, the farther it sees. (Lit. A bird which flies high sees afar.)

I think - ~고 생각해 (Opinion)

I think - ~고 생각해 (Opinion)

고 생각해 is usually used when you are expressing your opinion on something like what people should and shouldn't do and what people should and should not be allowed to do etc.

Refer to Have to - 해야 한다, Allowed to - 해도 된다 and I like doing - 하는게 좋다, 하는걸 좋아한다 to learn following examples.

Rules

Attach 고 생각해 to the present informal written form of verbs.
eg.

• 그걸 해야 한다고 생각해 = I think we should do it.
• 공원엔 가도 된다고 생각해 = I think it's OK to go to a park.
  
• 우유를 마시는게 좋다고 생각한다 = I think it's good to drink milk

Note: 그걸 = 그것을, 공원엔 = 공원에는

Example sentences

• 저녁에 일찍 자고 아침에 일찍 일어나야 된다고 생각해.= I think people should go to bed early at night and get up early in the morning.
  
• 건강해지기 위해 과일과 채소를 많이 먹어야 한다고 생각해. = I think people should eat a lot of fruits and vegetables to become healthy.
• TV는 많이 봐도 된다고 생각해요 = I think it's allowable to watch a lot of TV.
• 시간약속에 늦으면 안된다고 생각합니다 = I think it's not acceptable to be late for an appointment
• 책은 많이 읽는게 좋다고 생각한다 = I think it's good to read a lot of books. 
• 청량음료는 많이 마시지 않는게 좋다고 생각합니다 = I think it's not good to drink a lot of soft drinks.

I like doing - 하는게 좋다, 하는걸 좋아한다

I like doing - 하는게 좋다

하는게 좋다 is a contracted form of 하는 것이 좋다 (것이 → 게)
하는 것 means "doing" and if you remember, "가/이" is an identifier particle. I'd also like to call it a specificity particle.

For example,

• 점심에는 샌드위치 먹는 것이 좋다 = I like eating a sandwich at lunch (among a variety of things to eat at lunch, a sandwich is my choice)
  
• 시골에서 사는게 좋다 = I like living in the country (Although I could live in the city or urban area, I like living in the country)

좋다 means two things

• 1. I like
• 2. It's good

Usually, its meaning is "I like doing" in spoken Korean. In written Korean, "하는게 좋다" is more likely to mean "it's good to do something." However, the meaning depends on the context.

Informal	Positive	Negative
Written	하는게 좋다	하지 않는게 좋다 안하는게 좋다
Spoken	하는게 좋아	안하는게 좋아

Formal	Positive	Negative
Written	하는게 좋습니다	하지 않는게 좋습니다 안하는게 좋습니다
Spoken	하는게 좋아요	하지 않는게 좋아요 안하는게 좋아요

Note: The words in bold are the more commonly used alternatives of the two in each box.

Rules
1. Take 다 off a plain form of verbs and then attach 는게 좋다
2. If a verb has a final consonant of ㄹ, it is omitted.

• 하다 → 하는게 좋다 = I like doing, it's good to do
  
• 먹다 → 먹는게 좋다 = I like eating, it's good to eat
  
• 보다 → 보는게 좋다 = I like watching, it's good to watch
  
• 듣다 → 듣는게 좋다 = I like listening, it's good to listen
  
• 걷다 → 걷는게 좋다 = I like walking, it's good to walk
• 쓰다 → 쓰는게 좋다 = I like writing, it's good to write
  
• 읽다 → 읽는게 좋다 = I like reading, it's good to read
• 만들다 → 만드는게 좋다 = I like making, it's good to make
• 살다 → 사는게 좋다 = I like living, it's good to live
• 말다 → 마는게 좋다 = I like wrapping, it's good to wrap

Example sentences 

• 운동하는게 좋다 = I like exercising. It's good to exercise.
  
• 휴일에는 바닷가에 가는게 좋다 = I like going to the beach at weekends. It's good to go to the beach at weekends.
• 금요일밤에는 피자 먹는게 좋다 = On a Friday night, I like eating pizza. On a Friday night, it's good to eat pizza.
  
• 심심할땐 영화보는게 좋아 = When I'm bored, I like watching movies. When you're bored, it's good to watch movies.
  

I like doing - 하는걸 좋아한다

하는걸 is a contracted form of 하는것을 and 을 is an object particle.
하는걸 좋아한다 just means "I like doing"

Informal	Positive	Negative
Written	하는걸 좋아한다	하는걸 좋아하지 않는다 하는걸 안좋아한다
Spoken	하는걸 좋아해	하는걸 좋아하지 않아 하는걸 안좋아해

Formal	Positive	Negative
Written	하는것을 좋아합니다	하는것을 좋아하지 않습니다 하는걸 안좋아합니다
Spoken	하는걸 좋아해요	하는걸 좋아하지 않아요 하는걸 안좋아해요

Note: 걸 is a contracted form of 것을.

Rules are the same as above.

• 하다 → 하는걸 좋아한다 = I like doing
• 먹다 → 먹는걸 좋아한다 = I like eating
• 보다 → 보는걸 좋아한다 = I like watching
• 듣다 → 듣는걸 좋아한다 = I like listening
• 걷다 → 걷는걸 좋아한다 = I like walking
• 쓰다 → 쓰는걸 좋아한다 = I like writing
• 읽다 → 읽는걸 좋아한다 = I like reading
• 만들다 → 만드는걸 좋아한다 = I like making
• 살다 → 사는게 좋아한다 = I like living
• 말다 → 마는게 좋아한다 = I like wrapping

Example sentences

• 운동하는것을 좋아하지 않는다 = I don't like exercising.
• 휴일에는 바닷가에 가는걸 좋아한다 = I like going to the beach at weekends.
• 금요일밤에는 피자 먹는걸 좋아합니다 = On a Friday night, I like eating pizza.
• 심심할땐 영화보는걸 좋아해요 = When I'm bored, I like watching movies.

Update

I am embedding audio files to the posts. I hope that these audio files will help you with your listening skills and pronunciation. I am pretty impressed by the quality of the pronunciation of this computer-generated speaker. Her pronunciation of each letter is quite accurate and her intonation is pretty good. I encourage you to listen to these audios to practice your listening skills. I also recommend that you watch Korean TV programmes to improve your listening and speaking skills.

Allowed to - 해도 된다

Allowed to - 해도 된다 

Informal Form

Informal	are allowed to	were allowed to
Written	해도 된다	해도 됐었다
Spoken	해도 돼	해도 됐었어

Informal	aren't allowed to	weren't allowed to
Written	하면 안된다	하면 안됐었다
Spoken	하면 안돼	하면 안됐었어

Note:

해도 돼 means "allowed to do" and 안해도 돼 means "don't have to do," NOT "not allowed to do." This needs some explanations.

First of all, 돼 means "ok or allowed." 해도 돼 literally means "doing is ok." 안해도 literally means "not doing" therefore 안해도 돼 literally means "not doing is ok" which means "don't have to do."

하면 안돼 means "not allowed to do." 하면 literally means "if I do" and 안돼 means "not ok" therefore 하면 안돼 literally means "if I do it, it's not ok" which can be expressed as "not allowed to do"

Compare this with Have to - 해야 한다

However, you don't have to know these explanations to use them. Actually, I've never thought about why these mean what they mean until today. The best way to learn them is to use them frequently until they become memorised.

Rules 

1. Attach 도 된다/도 됐었다/도 돼/도 됐었어 to the positive informal spoken form of verbs Verbs - Present, Past 

• 해 → 해도 된다 = allowed to do
  
• 가 → 가도 된다 = allowed to go
  
• 봐 → 봐도 된다 = allowed to see
  
• 들어 → 들어도 된다 = allowed to hear
• 먹어 → 먹어도 된다 = allowed to eat
  
• 마셔 → 마셔도 된다 = allowed to drink
• 달려 → 달려도 된다 = allowed to run
  
• 앉아 → 앉아도 된다 = allowed to sit
  
• 놀아 → 놀아도 된다 = allowed to play/muck around

2a. Take 다 off a plain form of verbs without a final consonant and attach 면 안된다/면 안됐었다/면 안돼/면 안됐었어 to it. (Includes verbs with ㄹ as a final consonant)

• 하다 → 하면 안된다 = aren't allowed to do
  
• 가다 → 가면 안된다 = aren't allowed to go
• 춤추다 → 춤추면 안된다 = aren't allowed to dance
  
• 놀다 → 놀면 안된다 = aren't allowed to play/muck around
  
• 밀다 → 밀면 안된다 = aren't allowed to push
  
• 돌다 → 돌면 안된다 = aren't allowed to spin

2b. Take 다 off a plain form of verbs with a final consonant and attach 으면 안된다/으면 안됐었다/으면 안돼/으면 안됐었어 to it.

• 먹다 → 먹으면 안된다 = aren't allowed to eat
  
• 앉다 → 앉으면 안된다 = aren't allowed to sit
  
• 숨다 → 숨으면 안된다 = aren't allowed to hide
  
• 잡다 → 잡으면 안된다 = aren't allowed to catch
  
• 집다 → 집으면 안된다 = aren't allowed to pick up
  
• 접다 → 접으면 안된다 = aren't allowed to fold

Exceptions

• 듣다 → 들으면 안된다 = aren't allowed to listen
• 걷다 → 걸으면 안된다 = aren't allowed to walk
  

Example sentences
Written form

• 부페에서는 먹고 싶은 만큼 먹어도 된다 = At a buffet (restaurant), people are allowed to eat as much as they want.
• 시험을 마친 사람은 집에 가도 된다 = Those who have finished the exam can go home.
  
• 도서관에서는 크게 얘기하면 안된다. = It is not allowed to speak loudly in the library.
  
• 신생아들은 딱딱한 음식을 먹으면 안된다. = Infants are not allowed to eat solid food.
• 작년까지 학생들은 매점 자판기를 사용해도 됐었다 = Until last year, students were allowed to use a stall vending machine.

Spoken form

• TV 봐도 돼 = You are allowed to watch TV. (You can watch TV.)
• 이 케잌 먹어도 돼 = You are allowed to eat this cake. (You can eat this cake,)
• 술과 담배는 사면 안돼 = You are not allowed to buy alcohol and tobacco.
• 어제까지 놀아도 됐었어 = Until yesterday, I was allowed to muck around.
• 작년까지 빅토리아공원에는 들어가면 안됐었어 = Until last year, people were not allowed to enter the Victoria park.
  

Formal Form

Formal	are allowed to	were allowed to
Written	해도 됩니다	해도 됐었습니다
Spoken	해도 돼요	해도 됐었어요

Formal	aren't allowed to	weren't allowed to
Written	하면 안됩니다	하면 안됐었습니다
Spoken	하면 안돼요	하면 안됐었어요

Note: The rules are the same as above.

Example sentences
Written form

• 부페에서는 먹고 싶은 만큼 먹어도 됩니다 = At a buffet (restaurant), people are allowed to eat as much as they want.
• 시험을 마친 사람은 집에 가도 됩니다 = Those who have finished the exam can go home.
  
• 도서관에서는 크게 얘기하면 안됩니다. = It is not allowed to speak loudly in the library.
  
• 신생아들은 딱딱한 음식을 먹으면 안됩니다. = Infants are not allowed to eat solid food.
• 작년까지 학생들은 매점 자판기를 사용해도 됐었습니다 = Until last year, students were allowed to use a stall vending machine.

Spoken form

• TV 봐도 돼요 = You are allowed to watch TV. (You can watch TV.)
• 이 케잌 먹어도 돼요 = You are allowed to eat this cake. (You can eat this cake,)
• 술과 담배는 사면 안돼요 = You are not allowed to buy alcohol and tobacco.
• 어제까지 놀아도 됐었어요 = Until yesterday, I was allowed to muck around.
• 작년까지 빅토리아공원에는 들어가면 안됐었어요 = Until last year, people were not allowed to enter the Victoria park.
  

Have to - 해야 한다

Have to - 해야 한다


Informal form

Informal	Have to	Had to
Written	해야 한다 해야 된다	해야 했다 해야 됐다
Spoken	해야 해 해야 돼	해야 했어 해야 됐어

Informal	Don't have to	Didn't have to
Written	하지 않아도 된다	하지 않아도 됐다
Spoken	하지 않아도 돼 안해도 돼	하지 않아도 됐어 안해도 됐어

Note: The words in bold are the more commonly used alternative of the two in each box.

Rules
1. Attach 야 한다/야 된다/야 돼/야 됐어 etc. to the informal spoken form of verbs. Verbs - Present, Past

• 해 → 해야 한다 = have to do
  
• 가 → 가야 한다 = have to go
  
• 와 → 와야 한다 = have to come
  
• 봐 → 봐야 한다 = have to see
  
• 먹어 → 먹어야 한다 = have to eat
  
• 마셔 → 마셔야 한다 = have to drink

2. Take 다 off a plain form of verbs and then attach 지 않아도 된다/지 않아도 됐다/지 않아도 돼 etc. to it.

• 하다 → 하지 않아도 된다 = don't have to do
  
• 가다 → 가지 않아도 된다 = don't have to go
  
• 오다 → 오지 않아도 된다 = don't have to come
  
• 보다 → 보지 않아도 된다 = don't have to see
  
• 먹다 → 먹지 않아도 된다 = don't have to eat
  
• 마시다 → 마시지 않아도 된다 = don't have to drink

3. Attach 안 and 도 돼/ 도 됐었어 to the front and back of the informal spoken form of verbs respectively. Verbs - Present, Past

• 안해도 돼 = don't have to do
  
• 안가도 돼 = don't have to go
  
• 안와도 돼 = don't have to come
  
• 안봐도 돼 = don't have to see
  
• 안먹어도 돼 = don't have to eat
  
• 안마셔도 돼 = don't have to drink

Example sentences
Written Form

• 성민은 오늘 서울에 가야 한다. = Seong-min has to go to Seoul today.
• 민주는 내일 학교에 가지 않아도 된다. = Min-ju doesn't have to go to school tomorrow.
• 애쉴리는 병때문에 작년 매일 약을 먹어야 했다 = Because of her sickness, Ashley had to take (lit. eat) medicine everyday last year.

Spoken Form

• 이번 주 목요일까지 과학 과제 끝내야 돼 = I have to finish the science assignment by this Thursday.
• 애쉴리는 이제 다 나아서 병원에 안가도 돼 = Because Ashley has been healed now, she doesn't have go to the hospital.
• 고추가 너무 매우면 안먹어도 돼 = If the chillies are too spicy, you don't have to eat them.
  

Formal form

Formal	Have to	Had to
Written	해야 합니다 해야 됩니다	해야 했습니다 해야 됐습니다
Spoken	해야 해요 해야 돼요	해야 했어요 해야 됐어요

Formal	Don't have to	Didn't have to
Written	하지 않아도 됩니다 안해도 됩니다	하지 않아도 됐습니다 안해도 됐습니다.
Spoken	하지 않아도 돼요 안해도 돼요	하지 않아도 됐어요 안해도 됐어요

Note: The rules for the conjugation are the same as above.


Example sentences
Written Form

• 성민은 오늘 서울에 가야 합니다. = Seong-min has to go to Seoul today.
• 민주는 내일 학교에 가지 않아도 됩니다. = Min-ju doesn't have to go to school tomorrow.
• 애쉴리는 병때문에 작년 매일 약을 먹어야 했습니다 = Because of her sickness, Ashley had to take (lit. eat) medicine everyday last year.

Spoken Form

• 이번 주 목요일까지 과학 과제 끝내야 돼요 = I have to finish the science assignment by this Thursday.
• 애쉴리는 이제 다 나아서 병원에 안가도 돼요 = Because Ashley has been healed now, she doesn't have go to the hospital.
• 고추가 너무 매우면 안먹어도 돼요 = If the chillies are too spicy, you don't have to eat them.

Source: Learn Korean: LP's Korean Grammar Guide

Conjunctions - Because [때문에]

Conjunctions - Because [때문에; 왜냐하면, 때문이다]

때문에 is more frequently used in written Korean and ~서 is favoured in spoken Korean because of its brevity.

Rules  

Take 다 off a plain form and past tenses of verbs and adjectives and then attach 기 때문에. (But NOT a present tense of verbs ie. 한다 → 한기 때문에 is wrong! 하다 → 하기 때문에 is right!)  

• 하다 → 하기 때문에 = Because I do
  
• 가다 → 가기 때문에 = Because I go
• 사다 → 사기 때문에 = Because I buy
• 보다 → 보기 때문에 = Because I see
• 먹기 → 먹기 때문에 = Because I eat
• 좋아하다 → 좋아하기 때문에 = Because I like
  
• 했다 → 했기 때문에 = Because I did
• 갔다 → 갔기 때문에 = Because I went
• 먹었다 → 먹었기 때문에 = Because I ate
• 크다 → 크기 때문에 = Because it's big
• 작다 → 작기 때문에 = Because it's small
• 덥다 → 덥기 때문에 = Because it's hot
• 춥다 → 춥기 때문에 = Because it's cold
  
• 많다 → 많기 때문에 = Because there is a lot 
• 길다 → 길기 때문에 = Because it's long
• 맛있다 → 맛있기 때문에 = Because it's delicious 
• 높았다 → 높았기 때문에 = Because it was high 
  
• 예뻤다 → 예뻤기 때문에 = Because it was pretty
  
• 빨랐다 → 빨랐기 때문에 = Because it was fast
• 강했다 → 강했기 때문에 = Because it was strong

Example sentences 
- Compare and contrast 때문에 and ~서.

• 중국음식을 좋아하기 때문에 중국음식을 먹었다. = Because I like Chinese food, I ate Chinese food. (Written Korean)
• 중국음식 좋아하기 때문에 중국음식 먹었어요. = Because I like Chinese food, I ate Chinese food. (Spoken Korean)
• 중국음식 좋아해서 중국음식 먹었어요 = Because I like Chinese food, I ate Chinese food. (Spoken Korean) Conjunctions - Because, So
• 아침 일찍 학교를 가기 때문에 일찍 일어났다. = Because I go to school early in the morning, I got up early.
• 아침 일찍 학교 가서 일찍 일어났어요 = Because I go to school early in the morning, I got up early.
• 겨울에는 춥기 때문에 사람들은 따뜻한 옷을 입는다. = Because the winter is cold, people wear warm clothes.
• 겨울엔 추워서 사람들은 따뜻한 옷을 입어요 = Because the winter is cold, people wear warm clothes.
• 인터넷에는 잘못된 정보가 많기 때문에 무엇을 읽는지 조심해야 한다. = Because on the internet, there is a lot of false information, we should be careful about what we read.
• 인터넷엔 잘못된 정보가 많아서 뭘 읽는지 조심해야 되요. = Because on the internet, there is a lot of false information, we should be careful about what we read

Note: The object particle, 를/을, is omitted and some words are abbreviated in the spoken form. For example,

• 에는 →엔
• 무엇을 → 무얼 → 뭘
  

Although it is less commonly used, a sentence containing two clauses can be divided into two sentences using 왜냐하면 and 때문이다. 왜냐하면 is attached to the front of a second clause and 때문이다 replaces 때문에.

• 중국음식을 먹었다. 왜냐하면 중국음식을 좋아하기 때문이다. = I ate Chinese food because I like Chinese food.
• 중국음식 먹었어요. (왜냐면) 중국음식 좋아해서요. = I ate Chinese food because I like Chinese food.
• 일찍 일어났다. 왜냐하면 아침 일찍 학교를 가기 때문이다. = I got up early because I go to school early in the morning.
• 일찍 일어났어요. (왜냐면) 아침 일찍 학교 가서요. = I got up early because I go to school early in the morning.

Note:

왜냐하면 is abbreviated to 왜냐면 or it is altogether omitted in spoken Korean.

때문에 is mainly used in literature and the news reporters use it often. However, people still use 때문에 occasionally in conversations instead of ~서, especially when one wants to explain and reason.

Imperatives

Imperatives - 해, 하지마

Imperative	Positive	Negative
Informal	해 가 먹어	하지마 가지마 먹지마
Formal	해요 가요 먹어요	하지마요 가지마요 먹지마요
Honorific	하세요 가세요 드세요	하지마세요 가지마세요 드시지마세요

The informal form is used among very close friends or when talking to a younger person who is very close to you in informal situations.

The formal form and the honorific form are used in formal situations. However, if I were to choose which one to use, I would choose the honorific form because the formal form is a bit casual-ish. It is safe to use the honorific form if you are unsure which one to use.

Note: The honorific form of verbs is present in Korean such as:

먹다 → 드시다 = eat
자다 → 주무시다 = sleep
죽다 → 돌아가시다 = die, pass away

먹어's honorific form is 드세요. It is usually used when talking to people above your age or in formal situations.

Rules

Informal positive (Imperative) = Present positive (spoken Korean)

• 해! = Do!
• 저리 가! = Go over there! (Leave me alone!)
• 이 과자 좀 먹어. = Eat some of these snacks.
• 물 좀 마셔. = Drink some water.

Informal negative = Take 다 off a plain form of verbs and attach 지마 to it.

• 가지마! = Don't go!
• 이 영화는 보지마! = Don't watch this movie!
• 이거는 먹지마. = Don't eat this.
• 이 책은 읽지마. = Don't read this book.

Formal positive and negative = Attach 요 to informal forms

Honorific positive = 
1. Take 다 off a plain form of verbs and then attach 세요 to verbs without a final consonant.
2. Attach 으세요 to verbs with a final consonant.
3. For verbs with a final consonant of ㄹ, drop it off and attach 세요 to it.

• 가세요! = Please go!
• 이리 오세요. = Please come here.
• 빨리 떠나세요! = Please leave quickly!
• 어서 드세요. = Please eat already.
• 물고기 손으로 잡으세요. = Please catch the fish with your hands.
  
• 손 흔드세요! = Please wave your hands! (흔들다 = wave)
  
• 빙글빙글 도세요! = Please turn round and round! (돌다 = turn round, spin)
  

Honorific negative = Take 다 off a plain form of verbs and attach 지마세요.

• 장난 하지 마세요! = Please don't fool around!
• 저 곳에는 가지 마세요. = Please don't go to that place. (Keep away from that place.)
• 박물관에 있는 물건들은 만지지 마세요. = Please don't touch things in the museum.

Conjunctions - While

Conjunctions - While [~며/~(으)면서]

~며 form is more frequently used in written Korean while ~면서 is more frequently used in spoken Korean.

Rules

1. Take 다 off a plain form of verbs with no final consonant and add 며/면서 to it.

• 하다 → 하며/하면서 = while doing
  
• 가다 → 가며/가면서 = while going
  
• 주다 → 주며/주면서 = while giving
  
• 사다 → 사며/사면서 = while buying
  
• 보다 → 보며/보면서 = while watching
  
• 말하다 → 말하며/말하면서 = while speaking
• 마시다 → 마시며/마시면서 = while drinking
• 자다 → 자며/자면서 = while sleeping
  

2. Take 다 off a plain form of verbs with a final consonant and add 으며/으면서 to it.

• 먹다 → 먹으며/먹으면서 = while eating
• 받다 → 받으며/받으면서 = while receiving
• 찾다 → 찾으며/찾으면서 = while looking for
  
• 읽다 → 읽으며/읽으면서 = while reading

Exceptions

• 걷다 → 걸으며/걸으면서 = while walking
• 듣다 → 들으며/들으면서 = while listening

Example sentences

Written Korean

• 나는 운동을 하며/하면서 매트릭스를 봤다. = While doing exercise, I watched Matrix.
  
• 나는 노래를 들으며/들으면서 지리 공부를 했다. = While listening to music, I studied geography.
  
• 호머는 자며/자면서 코를 골았다. = While sleeping, Homer snored.
• 민지는 스타벅스에서 잡지를 읽으며/읽으면서 커피를 마셨다. = At Starbucks, while reading a magazine, Minji drank coffee.
  
• 준호는 차를 타고 회사를 가며/가면서 라디오를 들었다.  = While going to work by car, Junho listened to radio.

Spoken Korean

• 운동 하면서 매트릭스 봤어. = While doing exercise, I watched Matrix
• 노래 들으면서 지리 공부 했어. = While listening to music, I studied geography.
• (호머는) 자면서 코 골았어. = While sleeping, Homer snored.
• (민지는) 스타벅스에서 잡지 읽으면서 커피 마셨어. = At Starbucks, while reading a magazine, Minji drank coffee.
• (준호는) 차 타고 회사 가면서 라디오 들었어. = While going to work by car, Junho listened to radio.

매트릭스 = Matrix (The movie)
노래 = music, song
지리 = geography
호머 = Homer (a male name as in Simpsons)
민지 = Minji (a female name)
스타벅스 = Starbucks
잡지 = magazine
커피 = coffee
회사 = work, company
라디오 = radio
준호 = Junho (a male name)


Note:

The spoken Korean usually omits a subject because it is usually understood by the speakers as to who they are talking about. For example, if I were talking about myself, I wouldn't need to use 나는 to say something about me because it is assumed that I am talking about me.

Likewise, the third person subjects like 호머는 and 민지는 can also be omitted when a person being talked about is already known by people having a conversation.

The object particle, 를/을, is omitted in spoken Korean.