조동사 (능력, 허가, 요청, 제안, 의무, 금지, 충고, 과거의 습관, 추측, 가능성)

조동사 : 동작이나 상태를 의미하는 동사를 도와 그 동사만으로 표현하기 어려운 상세한 의미(허가, 추측, 요청, 의무 등)을 나타내는 동사

능력, 허가, 요청, 제안

현재동사	Shawn sings a Spanish song.
조동사 (능력)	He can sing a Spanish song.
(허가)	You may sing a Spanish song at the party.
(요청, 제안)	Could you sing a Spanish song for the guests?

(1) 조동사 + 동사원형

부정문 : 조동사 + not + 동사원형

의문문 : 조동사 + 주어 + 동사원형 ~?

(O) He can climb a rope ladder very well.

(X) He can climbs a rope ladder very well.

He can not climb on the roof. (cannot = can't)

Can he climb on the roof?

(2) 능력 : can (~할 수 있다.)

can = be able to로 바꿔 쓸 수 있다.

I can fix my computer.

(= I am able to fix my computer.)

I could climb trees very well when I was little.

(= I was able to climb trees very well when I was little.)

※ 조동사 두 개를 연달아 쓸 수 없다.

(X) will can -> (O) will be able to (~할 수 있을 것이다.)

I will be able to buy a new house next year.

(3) 허가 : can, may (~해도 좋다, ~해도 될까요?)

You can stay as long as you want.

You may go home if you don't feel well.

※ may는 추측에 가깝다.

Can I have some more bread? I am still hungry.

Could I have some more, please?

May I have some water, please?

공손함의 차이 : Can < Could < May

please만 있으면 공손함이 된다. please를 magic word라고도 불림.

(4) 요청, 제안 : can, could will, would, may, shall

(~해 주시겠어요?, ~할까요?)

Can you lend me $5?

Could you pick them up on your way home?

Will you give me a call before you leave?

Would you close the door, please?

Shall we dance?

Shall we go?

더 공손한 표현

can -> could

will - would

의무, 금지, 충고, 과거의 습관

금지, 의무	You must come back by 10 o'clock ~해야한다.
충고	You look pale. You had better see a doctor. ~하는 것이 좋다.
과거의 습관	When I had a dog, I would take him for a walk to the park. ~하곤 했다.

Must + 동사원형            >          have to + 동사원형          >         should + 동사원형
~해야한다 (의무)	~해야한다 (의무)	~해야한다 (충고)
공적인 의무	개인적인 의무	개인적인 의무 (내가 생각하기에)
부정 : must not + 동사원형 (~하지 마!)	부정 : don't have to + 동사원형 (~할 필요가 없다.)	부정 : should not(=shouldn't) (~해서는 안된다.)
과거 : had to

의무, 금지 : must, have to, should

(~해야 한다 must > should)

must의 과거 : had to

must의 미래 : will have to

must는 과거, 미래형이 없으므로 have to를 사용한다.

※ must not : ~하지 마! (금지)

don't have to : ~할 필요 없다 (불필요)

Our school has a dress code.

You must wear a school uniform.

(= You have to wear a school uniform.)

You must not wear jeans at school.

You don't have to wear a jeans at school.

충고 : had better, should

(~하는 것이 좋다)

그렇게 하지 않으면 문제가 생길 것이라는 의미가 포함된 강한 충고

had better의 부정 : had better not

James is waiting for you.

You had better hurry, or he will get angry.

(=You'd better hurry, or he will get angry.)

You had better not make any excuses.

There will not be enough seats in the restaurant.

You should reserve seats. You should not go without a reservation.

내가 생각하기에 좌석을 예약하고 가야 할거야. 예약 없이 가면 아마 안될거야.

과거의 습관 : would, used to

(~하곤 했다)

would : 과거의 습관 (동작)

used to : 과거의 습관 (동작, 상태) 만 가능하다.

On sunny days, we would go up the hill.

Sandra used to eat meat, but now she eats only vegetables.

(O) This place used to be a chocolate factory. (상태)

(X) This place would be a chocolate factory.

추측, 가능성

추측, 가능성 (불확실)	There might be a snowstorm tomorrow. ~일지도 모른다
(확신)	He must be tired now. He walked for 3 hours. ~임에 틀림없다.

(1) 불확실한 추측, 가능성 (~일 수도 있다.)

※ might는 may의 과거가 아니다. may보다 확신이 덜 한 경우 might를 쓴다.

※ 추측의 may는 It is possible that ~으로 바꿔 쓸 수 있다.

불확실한 추측, 가능성 : may, might, could

I haven't seen Danny these days.

He may[might] be very busy with his work.

Where is Kim?

I'm not sure. He could be in the library.

확신을 나타내는 추측 : must, cannot

must : ~임이 틀림없다.

cannot : ~일 리가 없다.

There's someone at the door.

It must be Sam. He told me he would come by.

George stole the money.

It can't be true! He is a very honest man!