MODALS

Auxiliary

Use

Present

Past

must

Certainty

You look pale. You must be sick.

He is yawning and rubbing his eyes. He must be sleepy.

You looked pale. You must have been sick.

He was yawning and rubbing his eyes. He must have been sleepy.

Can’t

Impossibility

Rachida looks young. She can’t be forty.

They have just got married. They can’t have any children.

Rachida looked young. She can’t have been forty.

I rang the bell several times and no one answered me. They couldn’t have been at home.

May, can, might

Possibility

Our team can/may/might win the match next Sunday.

You can find the answer if you concentrate more.

Our team might have won the game if the referee had blown the whistle for the penalty.

You could have found the answer if you had concentrated more.

Must / have to

Obligation

Drivers must stop when the light is red.

I have to put on my coat because it is cold.

They had to stop when the light was red.

I had to put on my coat because it was cold.

Should / ought to

Obligation

You should have a medical check-up every year.

Drivers ought to maintain their vehicles.

I should have had a medical check-up last year.

He ought to have maintained his car before the accident.

EXERCISES:

I rang the doorbell several times. No one (be) at home. They (go) out.
I see a crowd of people gathered around a person whose leg is bleeding. His damaged bicycle dropped on the floor. There (be) an accident.
People (eat) to live.
People (eat) a balanced diet.
People were poor in the past, so their children (look for) a job to help their families.
In order to promote the society, we (empower) women.
Brahim (be not) sick. I saw him at the café this morning. He looked great!
She is an average student. She (pass) the exam.
A: Where’s Hasna?
B: She (be) at the library.
There are some clouds in the sky. It (rain) rain this afternoon.
You (tell) the truth yesterday in stead of hiding the secret. They will discover it sooner or later.
The students are making noise in class right now. Their teacher (be) out.
All the students answered the questions of the test in a short time last Monday. The test (be) easy. It (be not) difficult.
The rich (help) the poor.
I (work) hard last year to pass my exam.
He doesn’t have any friends. He always goes alone. He (be) a foreigner.
Teachers (help) their students not only at school, but outside school also.
When I was preparing for my baccalaureate exam, I (get up) early everyday.
Immigrants (adapt) the customs and traditions of their host country.