MODAL + PERFECT MODAL VERBS

1. WHAT ARE MODAL VERBS?

Modal verbs are auxiliary verbs that help express different functions such as
ability, possibility, permission, obligation, advice, and more. They always go
with the base form of the main verb (the infinitive without to).

KEY CHARACTERISTICS OF MODAL VERBS:

• They do not change with the subject. (No -s in third person singular)

She cans speak English. // She can speak English.

• They are followed by the base form of the verb. (We do not conjugate the
verbs after the modals neither in person nor in number)

She can speaks English. // She can speak English.

• They form questions and negatives without auxiliary verbs (Do/Does/Did).

Does she can speak English? // Can she speak English?
COMMON MODAL VERBS AND THEIR USES:

Modal
Use Example
Verb

I can play the guitar. (ability) // Can I leave

Ability, possibility, early? (permission)
Can
permission

Past ability, possibility, She could read when she was five. // Could
could
polite requests you help me, please? (polite requests)

Formal permission, May I speak now? (permission) / It may rain

may
possibility later. (possibility)

Possibility (less certain He might be at home now.

might
than may)

Strong obligation,
deduction You must wear a seatbelt. (obligation) / She
must
must be tired after the trip. (deduction)

Advice, recommendation,
should expectation You should apologize to her. (advice)

Suggestions, offers
shall Shall we go for a walk?
(formal)

Future actions, promises, I will call you tomorrow.

will
certainty

Hypothetical situations, I would help you if I could. (hypothetical) /

would
polite requests Would you like some tea? (polite offer)
had Strong advice,
You had better study for the exam. (strong advice)
better warning

I am able to solve this problem. (present) / She was able

be able Ability (all
to finish on time. (past) / They will be able to join us later.
to tenses)
(future)

don’t Lack of You don't have to come if you are busy. (it's not
have to necessity necessary)

don’t Lack of
You don't need to bring anything. (it's not necessary)
need to necessity

2. HOW TO FORM QUESTIONS AND NEGATIVES WITH MODALS?

• Questions: Place the modal before the subject.

o Can you help me?

▪ Yes, I can.

▪ No, I cannot.

o Should we start now?

▪ Yes, we should.

▪ No, we should not.

• Negatives: Add not after the modal.

o You should not be late.

o He might not come today.

 3. PERFECT MODALS (MODAL + HAVE+ PAST PARTICIPLE)

We use perfect modals to talk about past situations: to express possibility,

probability, regret, obligation, or hypothetical situations in the past.

• Structure:

Modal + have + past participle

(must have gone, could have seen, should have done, etc.)

COMMON PERFECT MODALS AND THEIR USES:

Example
Perfect Modal Use

Strong deduction about She must have left already. (I’m sure
must have + PP
the past she left.)

They might have forgotten the

might/may
Past possibility appointment. (It’s possible they
have + PP
forgot.)

could have + Past possibility or He could have won the race, but he
PP unrealized ability didn’t try.

should have + Regret, criticism, or past You should have told me the truth. (It
PP advice was a mistake not to tell me.)

Hypothetical past
would have + I would have helped you if I had
situations (3rd
PP known.
conditional)
 4. KEY DIFFERENCES BETWEEN MODALS AND PERFECT MODALS:

• Modals = Present/Future situations

o She must be tired. (present deduction)

• Perfect Modals = Past situations

o She must have been tired. (past deduction)

5. PRACTICE EXERCISES:

A. Complete the sentences with the correct modal verb:

1. You _____ (can/must/should) study if you want to pass the exam.

2. He _____ (may/must/could) be at home; I saw his car outside.

3. _____ (Can/May/Should) I borrow your pen?

B. Rewrite the sentences using perfect modals:

1. I’m sure she forgot the meeting. → She ____________________.

2. It was a mistake not to call her. → I ____________________.

3. Maybe they left early. → They ____________________.

C. Error Correction:

1. She must has gone to the party. → ________

2. I should told you the truth. → ________

3. He could helped me yesterday. → ________

6. QUICK TIPS TO REMEMBER:

• Modals + Base form of the verb. (She can swim.)

• Perfect Modals = Modal + have + past participle. (She could have gone.)

• Modals don’t change with the subject. (He must go, They must go.)