Grammar - Modals - Might, may, could and can

We can use Modal verbs  not only to speak about obligation or possibility, etc. but also to speak about  “deductions”. Most foreign students prefer to use the words ‘probably’, ‘perhaps’ or ‘maybe’ to express situations they are unsure of, but it is common for native speakers to use Modal verbs instead.

must

We use must when we feel sure that something is true because there’s very strong evidence.

·         He must live near here because he comes to work on foot. We don’t know where he lives but we’re sure it’s not far away.

·         Come inside and get warm – you must be freezing out there.

·         You’re a zookeeper? That must be very interesting.

·        
might, may, could

We use might, may or could to say that we think something is possible but we’re not sure.

·         Did you hear that? I think there could be a burglar downstairs. She’s not sure there’s a burglar but she thinks it’s possible.

·         He should be here by now but he might be stuck in traffic as it’s rush hour.

·         I’m not sure who they’ll select, but it may be Dan.

can’t

We use can’t when we feel sure something is not true.

·         It can’t be a burglar. All the doors and windows are locked. He doesn’t know it’s not a burglar but he feels sure it’s not.

·         It can’t be far away now. We’ve been driving for hours. Where’s the map?

·         Really? He has to work on Christmas Day? He can’t feel very happy about that.

Remember that all of these modal verbs – must, might, may, could and can’t have other uses.