[Modal auxiliaries] Degrees of Certainty: Future Time

100% sure	Kay will do well on the test
90% sure	Kay should do well on the test.
	Kay ought to do well on the test.
50% sure or less	She may do well on the test.
	She might do well on the test.
	She could do well on the test.

[Modal auxiliaries] Degrees of Certainty: Past Time Negative

100% sure	Sam wasn't hungry.
99% sure	Sam couldn't have be hungry.
	Sam can't have be hungry.
95% sure	Sam must not have be hungry.
50% sure or less	Sam may not have be hungry.
	Sam might not have be hungry.

[Modal auxiliaries] Degrees of Certainty: Past Time Affirmative

100% sure	Sam wasn't hungry.
99% sure	Sam couldn't have be hungry.
	Sam can't have be hungry.
95% sure	Sam must not have be hungry.
50% sure or less	Sam may not have be hungry.
	Sam might not have be hungry.

[Modal auxiliaries] Degrees of Certainty: Present Time Negative

100% sure	Sam isn't hungry.
99% sure	Sam couldn't be hungry.
	Sam can't be hungry.
95% sure	Sam must not be hungry.
50% sure or less	Sam may not be hungry.
	Sam might not be hungry.

[Modal auxiliaries] Degrees of Certainty: Present Time Affirmative

100% sure	He is sick.
95% sure	He must be sick.
50% sure or less	He may be sick.
	He might be sick.
	He couble be sick.

[Modal auxiliaries] Making Suggestions: Couhd vs. Should

I would have	(reason)
I should have	forget, choice
I could have	choice
can, could	ability
could may might	possibility

Should have (用在應該/可能發生而沒有發生的事物)

例：昨晚你應該來我的生日晚會， 大家都想念你

錯誤：	You should come to my birthday party last night, everyone missed you.
正確：	You should have come to my birthday party last night, everyone missed you.

example

I broke my iPhone 9, but thankfully I still have the warranty. It covers my phone for a year. Now, what am I supposed to do?

A. You have it checked already.

B. You should have replaced it.

C. You have to get replaced.

You should have it replaced.

Should not have (用在不應發生卻發生了的事物)

昨晚你不應該出去， 否則現在你的作業就已經作完了

You should not have gone out last night or you would have your homework finished by now.

「or 在此作 “否則” 解；would have 則有假定意涵」

Would have (會發生卻沒有發生的事物/情況)

今天如果你的父親還活著， 他會很高興看到你的成功

Your father would  have been very happy to see your success had he been living today.

這裡的 “會發生”,  是指你父親會很高興的機率， 不是指他會活到今天的機率」

Would not have (不會發生卻發生了的事物/狀況)

今天如果他小心一點的話， 這件事就不會發生

This matter would not have happened had he been more careful today.

This matter would not have happened ,if he had been more careful today

[Modal auxiliaries] Making Suggestions: Let's/Why don't/Shall I/We

Let's go for a drink! (One of your close friends.)

Why don't we go for a drink! (A secret admirer)

Shall we go for a drink? (A handsome gentleman)

Let's go, shall we? (正式)

Let's go, okay? (非正式)

未來式

Let's go to a movie tomorrow.

Why don't we go to a movie tomorrow?

Shall we go to a movie tomorrow?

1.

A: A new Japanese restaurant just opened downtown. Let's eat there tonight.

B: Great idea! I'd like some good sushi.

A: Why don't you(not we) call and make a reservation (訂位只有一人)? Make it for about 7:30.

B: No, let's make it for 8:00. I'll be working until 7:30 tonight.

4.

A: Shall we go to the office or have dinner first?

B: Let's go to the office first; then we can take our time over dinner.

A: Why don't we go to Bella Monica?

Shall 有劃好要去

Why don't we 沒計劃

[Modal auxiliaries] Unfulfilled Intentions: Was/Were going to

i’m going to go the concert tomorrow.	used to talk about intentions for future activities.
Jack was going to go to the movie last night, but he changed his mind.	Was/were going to talks about past intentions.
I was planning to go, but I didn't.	Other ways of expressing unfulfilled intentions are to use plan, hope, intent….
I was hoping to go, but I couldn't.
I was intending to go, but I didn't.
I was thinking about going, but I didn't
I had hoped to go, but I couldn't.
I had intended to go, but I didn't.
I had thought about going, but I didn't.
I had planned to go, but I changed my mind.

[Modal auxiliaries] Advisability: had better/should/ought to

You ‘d better take care of it. Had better = 'd better	Sometimes in speaking, had is dropped. 注意：沒有 have better
We should at least be wrinkle-free. Drivers should obey the speed limit.
I ought to (“otta”) study tonight, but I think I’ll watch TV instead.	Ought to is not commonly used in the negative. If it is, the to is sometimes dropped: You oughtn’t (to) leave your keys in the car.

[Modal auxiliaries] Lack of Necessity and Prohibition: have To and Must in the Negative

When used in the negative, must and have to have different meanings.

Lack of necessity
I can hear you. You don’t have to shout.	May also be expressed by need not + the simple form of a verb
Prohibition
You must not tell anyone my secret. Do you promise?
Don’t tell anyon my secret.
You can’t tell anyone my secret.
You’d better not tell anyone my secret.

[Modal auxiliaries] Using be supposed to

Mike is supposed to call me tomorrow.

(IDEA: I expect Mike to call me tomorrow.)

Alice was supposed to be home at ten, but she didn't get in until midnight.

(IDEA: Someone expected Alice to be home at ten.)

The teacher expects us to be on time for class.

We are supposed to be on time for class.