Must (have) and can’t (have)

Must (have) and can’t (have)

Study this example situation:این مثال را بخوانید

Liz is a very good tennis player, and not many players beat her. But yesterday she played against Bill and Bill won. So:

Bill must be a very good player (otherwise he wouldn’t have won).

We use must to say we are sure that something is true:از must زمانی استفاده میکنیم که مطمئن هستیم چیزی صحیح است.

You’ve been traveling all day. You must be tired. (= I am sure that you are

tired.)

I hear that your exams are next week. You must be studying very hard right now. (= lam sure that you are studying.)

Carol knows a lot about films. She must like to go to the movies. (= I am

sure she likes to go to the movies.)

We use can’t to say that we think something is impossible: از can’t زمانی استفاده میکنیم که فکر میکنیم چیزی غیر ممکن است.

You’ve just had dinner. You can’t be hungry already. (= It is impossible that you are hungry.)

Tom said that he would be here ten minutes ago, and he is never late, He can’t be coming.

For the past we use must have (done) and can’t have (done). Study this example:

We went to Roy’s house last night and rang the doorbell. There was no answer. He must have gone out (otherwise he would have answered).

The phone rang, but I didn’t hear it. I must have been asleep.

I made a lot of noise when I came home. You must have heard me.

She passed me on the street without speaking. She can’t have seen me.

Tom walked into the wall. He can’t have been looking where he was goit

“Couldn’t have (done)” is possible instead of “can’t have (done)”:

 She couldn’t have seen me.

• He couldn’t have been looking where he was going.