Can, Could, Should, Must

General

100

What is 'can' used for?

Express ability

200

What is 'could' used for?

Express ability in the past

300

What is 'must' used for?

To express obligation

400

What is 'mustn't' used for?

To express prohibition

500

What is 'should' used for?

To give advice

Positive

100

I ________ play the guitar and the piano. 

CAN

200

When I was little, I _______ run 10km but now I ______.

COULD, CAN'T

300

You _________ listen to your parents when they give you advice. They want what's best for you.

SHOULD

400

They _______ be quiet when the teacher is speaking. They are not allowed to talk.

SHOULD

500

You ________ study for your exams, and for that, you _______ have an organized timetable.

MUST, SHOULD

Negative

100

He ________ visit me last week because his car didn't work.

COULDN'T

200

They _________ go to bed late if they want good grades.

SHOULDN'T

300

I used to be very good at Maths, but now I ________ understand the problems.

CAN'T

400

You _______ smoke inside bars. It's prohibited.

MUSTN'T

500

When I was young I ________ read a book in a day, and now I still _______ do it. It's too difficult.

COULDN'T, CAN'T

Interrogative

100

I don't know the rules in this school. _________ (wear, I) a uniform? Is it obligatory?

MUST I WEAR

200

I don't know what to do. _______ (I, text) him?

SHOULD I TEXT

300

Wow, you can play football very well! ________ (you, do) it when you were young, too?

COULD YOU DO

400

I don't know her very well. __________ (she, swim) faster than me?

CAN SHE SWIM

500

________ (he, ride a bike) when he was at school or _________ (he, only, do) it now?

COULD HE RIDE A BIKE, CAN HE ONLY DO