Possibility and certainty: may, might, could, must, etc
A May, might and could
Rachel: Whose bag is that?
Daniel: / don't know. It may belong to Maria's friend.
Vicky: It might be a bomb. It could explode at any moment.
We use may or might to say that something is possible or that it is quite likely.
We can use them for the present or the future.
It may/might be a bomb. (= Perhaps it is a bomb.)
/ may/might go to the disco tomorrow. (= Perhaps I will go to the disco.)
We can use could to say that something is possible.
The story could be true, I suppose. (= Possibly it is true.)
You could win a million pounds! (= Possibly you will win a million pounds.)
Sometimes could means only a small possibility. It is possible (but not likely) that
you will win a million pounds.
In some situations we can use may, might or could. It may/might/could rain later.
After may, might or could we can use a continuous form (be + an ing-form). That man may/might be watching us. (= Perhaps he is watching us.) Sarah may/might be working late tonight. (= Perhaps she will be working late.) I'm not sure where Matthew is. He could be playing squash. (= Possibly he is playing squash.)
B May, might and could in the negative
The negative forms are may not, might not/mightn't, and could not/couldn't.
MAY NOT AND MIGHT NOT
Something negative is possible. Daniel may not get the job. Tom might not be in. I mightn't finish the marathon tomorrow. (It is possible that I will not finish it.)
couldn't
Something is impossible.
Vicky is afraid of heights. She couldn't climb
onto the roof.
I'm completely unfit. I couldn't run a marathon. (It is impossible for me to run it.)
C Must and can't
MUST
We use must when we realize that something is certainly true.
She isn't answering the phone. She must be out. I had my keys a moment ago. They must be here
somewhere.
Andrew isn't here. He must be working in the library.
CANT
We use can't when we realize that something is impossible.
We haven't walked far. You can't be tired yet. Life can't be easy when you have to spend it in a
wheelchair.
Nick can't be touring Scotland. I saw him hat this morning.
53 Might/could/must have been page 379 Mustn't in American English t> 51A Could in suggestions
46 Exercises
1 Might be and might be doing (A)
Vicky and Rachel are at college. They're looking for their friend Natasha. Complete the conversation.
Use may or might and the verb in brackets. Sometimes you need to use the continuous.
Vicky: I can't find Natasha. Have you seen her?
Rachel: (►) She might be (she / be) in the music room. (►) She may be practising (she / practise).
Vicky: No, she isn't there. I thought (1) . (she / be) with you.
Rachel: It's a nice day. (2) (she / be) on the lawn.
(3) .. (she / sit) out there reading the paper.
Or (4) (she / have) a coffee.
(5) ..(you / find) her in the canteen.
Emma: No, I've looked there.
Rachel: Well, here comes Jessica. (6) . (she / know).
2 May and might (A-B)
Add a sentence with may or might (both are correct).
? I'm not sure if it's going to rain. It might rain.
? I don't know if we'll see an elephant. We may see one.
1 I can't say whether Daniel will win...................................................................................................................... ..
2 I haven't decided if I'm having a holiday. ........................................................................ ...
3 I don't know if we'll get an invitation. ...........................................................................................................
4 I've no idea whether Sarah will be late..........................................................................................................................
3 I'm not sure if my friends are visiting me.................................................................................................. .
3 Mightn't and couldn't (B)
Put in mightn't or couldn't.
? I've got one or two things to do, so I mightn't have time to come out tonight.
? David couldn't work as a taxi driver. He can't drive.
1 We're going to need lots of glasses. We...................................................... have enough, you know.
2 Mark be in the office tomorrow. He thinks he's getting a cold.
3 We . possibly have a dog, living in a small flat like this.
■1 How can you work with all this noise? I ............... work in such conditions.
5 Don't ring tomorrow because I...................................................... be in. I'm not sure what I'm doing.
4 Must, can't and might (A, C)
A reporter is interviewing Mrs Miles for a TV news programme.
Complete the conversation. Put in must, can't or might.
Mrs Miles: My name's Nora Miles, and I'm going to do a parachute jump.
Reporter: Mrs Miles, you're seventy-three, and you're going to jump out of an aeroplane.
You (►) must be mad. You (1) .................................................... be serious.
Mrs Miles: It really (2) ..be wonderful to look down from the sky.
I've always wanted to try it. Reporter: But anything could happen. You (3)......................................................... be injured or even killed.
I wouldn't take the risk. Mrs Miles: Well, young man, your life (4) .. be much fun if you never take risks.
You ought to try it. You never know - you (5) enjoy it.
Reporter: Enjoy it? You (6) ....................................................... be joking!