1. CAN, CAN’T (CANNOT) - ABILITY/POSSIBILITY/PERMISSION/REQUESTS
AFFIRMATIVE
|
NEGATIVE
|
INTERROGATIVE
|
I can read.
|
I can’t / cannot swim.
|
Can I go to the toilet?
|
You can read.
|
You can’t / cannot swim.
|
Can you go to the
toilet?
|
He /she /it can read.
|
He /she /it can’t / cannot swim.
|
Can he /she / it go to
the toilet?
|
We can read.
|
We can’t / cannot swim.
|
Can we go to the
toilet?
|
You can read.
|
You can’t / cannot swim.
|
Can you go to the
toilet?
|
They can read.
|
They can’t / cannot swim.
|
Can they go to the
toilet?
|
SHORT ANSWERS (+, -)
|
Yes, subject + CAN.
|
No, subject + CAN’T.
|
"BE ALLOWED TO": Only form which is used to ask for permission in all tenses. "CAN" is only used in the Present Simple and "COULD" is only used in the Past Simple and in the Conditional tense.
"BE ABLE TO": Only form which is used to express ability in all tenses. "CAN" is only grammatically possible in the Present Simple and "COULD" is only grammatically possible in the Past Simple and in the Conditional tense.
2 MUST: OBLIGATION (Affirmative) ≠ MUSTN'T: PROHIBITION (Negative) - RULES
2 MUST: OBLIGATION (Affirmative) ≠ MUSTN'T: PROHIBITION (Negative) - RULES
I must
study.
|
I mustn’t
/ must not smoke.
|
You must
study.
|
You mustn’t
/ must not smoke.
|
He / she / it must study.
|
He / she / it mustn’t / must not smoke.
|
We must
study.
|
We mustn’t
/ must not smoke.
|
You must
study.
|
You
mustn’t / must not smoke.
|
They must study.
|
They mustn’t / must not smoke.
|
MUST:
- Formal writing.
- "Internal" obligation (personal opinion, family, friends). // Also: Strong recommendation.
- "Must" in questions: It is grammatically correct, but "have to" is more frequently used in interrogative sentences.
- Attention: It is only used in the Present Simple. For the other tenses, use "HAVE TO".
HAVE TO:
- More frequent in conversation.
- "External"
obligation (somebody in authority, at work, law).
- Attention: "Have got to" is also possible, but it is more informal than "have to".
3. HAVE
TO, NEED TO: OBLIGATION, NECESSITY ≠ DON’T HAVE TO/ NEED TO (“NEEDN’T”): NO
OBLIGATION, NO NECESSITY
HAVE TO /
NEED TO
|
DON’T HAVE
TO / DON’T NEED TO (NEEDN'T)
|
I have
to / need to speak English in class.
|
I don’t
have to pay. It’s free.
I don’t need to pay / I needn’t pay.
|
You have
to / need to speak English in class.
|
You don’t
have to pay. It’s free.
You
don’t need to pay / You needn’t pay.
|
He/she/ it has to / needs to speak English in class.
|
He/she doesn’t have to pay. It’s free.
He
doesn’t need to pay / He needn’t pay.
|
We have
to / need to speak English in class.
|
We don’t
have to pay. It’s free.
We don’t need to pay / We needn’t pay .
|
You have
to / need to speak English in class.
|
You don’t
have to pay. It’s free.
You
don’t need to pay / You needn’t pay
|
They have to / need to speak English in class.
|
They
don’t have to pay. It’s free.
They don’t need to pay / They
needn’t pay.
|
4. SHOULD, SHOULDN’T (SHOULD
NOT)- ADVICE
AFFIRMATIVE
|
NEGATIVE
|
INTERROGATIVE
|
I should do exercise.
|
I shouldn’t / should not eat a lot of
sweets.
|
Should I go to the gym?
|
You should do exercise.
|
You shouldn’t / should not eat a lot of
sweets.
|
Should you go to the gym?
|
He/she/it should do exercise.
|
He/she/it shouldn’t / should not eat a lot of
sweets.
|
Should he/she/ it go to
the gym?
|
We should do exercise.
|
We shouldn’t / should not eat a lot of
sweets.
|
Should we go to the gym?
|
You should do exercise.
|
You shouldn’t / should not eat a lot of
sweets.
|
Should you go to the gym?
|
They should do exercise.
|
They shouldn’t / should not eat a lot of
sweets.
|
Should they go to the gym?
|
SHORT ANSWERS (+, -)
|
Yes, subject + SHOULD.
|
No,subject SHOULDN’T.
|
OUGHT (NOT) TO + INFINITIVE:
It has got the same meaning as "should", but it is much more formal and it is not frequently used in spoken conversations.
HAD BETTER (NOT) + INFINITIVE: ("más te vale")
It is slightly different to "should" and "ought to", because it implies there is a negative consequence to (not) performing the action.
5 MAY - POSSIBILITY, PERMISSION* MIGHT- REMOTE POSSIBILITY
|
I may / may not come. |
I might / might not come. |
|
You may / may not come. |
You might / might not come. |
|
He / she / it may / may not come. |
He / she / it might / might not come. |
|
We may / may not come. |
We might / might not come. |
|
You may / may not come. |
You might / might not come. |
|
They may / may not come. |
They might / might not come. |
