Modal verbs

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- I (a)   swim because I learnt when I was younger.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- People (a)   speak while eating, but there are some people who still do it.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- I'm sure you (a)   write when you were two years old.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- If the teacher is speaking you (a)   interrupt.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- If she's not feeling well, she (a)   come to the party.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- You (a)   leave without my permission, that's all.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

He (a)   climb really fast when he was twenty, but now he's out of shape.

Use can, can't, could, couldn't, don't have to, doesn't have to, must and mustn't:

- Students (a)   listen to their teachers in class, it's mandatory.

(a)   you help me, sir? I cannot find the train station.

People who (a)   speak a second language usually find difficult to start a new life abroad.