MODAL VERBS
FUNCTIONS
1. ABILITY (khả năng, năng
lực)
2. FUTURE POSIBILITY (có
thể xảy ra trong tương lai)
3. REQUEST (yêu cầu)
4. OFFER (đề nghị)
5. PERMISSION (xin phép)
6. ADVICE, OBLIGATION,
NECESSITY (lời khuyên, sự
bắt buộc, sự cần thiết)
7. PROHIBITION (cấm)
8. LOGICAL ASSUMPTION
(giả định có căn cứ)
9. PREFERENCE (sở thích)
10. SOMETHING IN
PROGRESS IN THE PRESENT
(một việc đang diễn ra ở
hiện tại)
11. SOMETHING IN
PROGRESS IN THE PAST (một
việc đang diễn ra ở quá khứ)
12. SOMETHING HAPPENED
IN THE PAST (một việc xảy ra
trong quá khứ)
MODAL VERBS
Can, could, be
able to
EXAMPLES
He can speak five languages
We will be able to swim very fast after this
swimming course
May, might, can, He may win the race
could, be likely to She will leave tomorrow. She’s ready now.
Can, could, will,
Can you close the door?
would
Could you please help me with this exercise?
Answer by Can or Will, or OK, Sure, Sorry, …
Can / Shall I /
Can I help you?
Shall we
Shall we do it for you now?
Answer by OK, thanks; That would be nice,…
Can / could / may Can we go to the movies tonight?
May I leave early today?
Answer: Sure, Go ahead, Certainly,…
Should, ought to, Students ought not to do too much
had better,
homework
have to, must,
You’d better study for the test if you don’t
have got to,
want to fail.
be to
I am to be at the airport by 4 pm tomorrow
Must not
They mustn’t bring pets into this restaurant
Must, may,
You have worked all night these days. You
Can’t, couldn’t,
must be very tired.
might not
Tom couldn’t be at the library now. I just saw
him five minutes ago.
Would like, would I would prefer to watch this film.
prefer, would
I would rather eat at home.
rather
Would prefer not,
Would rather not
Modal + be + VTom is in the library now. He must be
ing
studying for his test tomorrow.
Don’t call me tonight. I could be going to the
movies with my family.
Modal + have
Sue wasn’t at home last night when we went
been + V-ing
to visit her. She might have been studying at
the library.
Modal + have +
PP
- advice (should / She should have studied hard during the
ought to) (lời
course last semester (but she didn’t)
khuyên)
- prediction (dự
The grass is all wet. It must have rained very
đoán)
hard last night.
Marry can’t have been at home. She ate out
with me.
- unreal condition
in the past (If 3)
- unnecessary
things
-ability
If I had known they were vegetarians, I would
have made a salad.
You needn't have washed the dishes. I
would've put them in the dishwasher.
I could have stayed up late, but I decided
to go to bed early.
DEGREE OF CERTAINTY
1. PRESENT TIME
a) Affirmative
- Why isn’t John in class?
100% sure:
95% sure:
Less than 50% sure:
b) Negative
100% sure:
99% sure:
95% sure:
Less than 50% sure:
He is sick.
He must be sick.
He may be sick.
He might be sick.
He could be sick.
Sam isn’t hungry.
Sam couldn’t be hungry.
Sam can’t be hungry.
Sam must not be hungry.
Sam may not be hungry.
Sam might not be hungry.
2. PAST TIME
a) Affirmative
- Why wasn’t Mary in class?
100% sure:
She was sick.
95% sure:
She must have been sick.
She may have been sick.
Less than 50% sure:
She might have been sick.
She could have been sick.
b) Negative
- Why didn’t Sam eat?
100% sure:
Sam wasn’t hungry.
99% sure:
Sam couldn’t have been hungry.
Sam can’t have been hungry.
95% sure:
Sam must not have been hungry.
Less than 50% sure:
Sam may not have been hungry.
Sam might not have been hungry.
3. FUTURE TIME
100% sure:
90% sure:
Less than 50% sure:
Kay will do well on the test.
Kay should do well on the test.
Kay ought to do well on the test.
Kay may do well on the test.
Kay might do well on the test.
Kay could do well on the test.