Modals of Deduction

Modals of deduction

must, can't, could, may, might

We can use

 MUST, MAY, MIGHT, COULD and CAN'T to express how sure we are about something happening in the present or the future.

MUST

We use must when we feel sure about something because there is some kind of evidence.

e.g.   She must study very hard because she gets really good marks.

CAN'T

We use can't when we are sure something is not true.

e.g. You have been sleeping all day. You can't be tired.

MAY, MIGHT, COULD

We use may, might and could when are not sure about something, but we think it is possible.

e.g. She might go to the party tomorrow if you ask her. 

e.g. Peter could be at the library. He said he was going to go one of these days.

e.g. They may win the match. They are quite good.

***They all have the same meaning, but may is more formal than might and could.

Time to practise!

Multiple Choice

The house isn't hard to find. It's the red one at the end. You _____ miss it!

• must

• can't

• could

Multiple Choice

Look at that bird! Maybe it's an eagle or it _____ be a vulture.

• must

• could

• can't

Multiple Choice

What an amazing trip! You _____ have some incredible photos.

• must

• might

• can't

Multiple Choice

Have you got your passport? I'm not sure if you'll need it but they _____ ask you for ID.

• can't

• must

• might

Open Ended

Write 5 sentences using the modals of deduction

(must, can't, may, might, could)