Modal verbs for speculation: must, can't, may / might, could

1 Choose the correct options to complete the sentences.

Tom’s walked a really long way today. He ___ be tired.

Take an umbrella with you because it ___ rain later. 

Ben always gets 100% in his Maths tests. He ___ be clever. 

The phone’s ringing. It ___ be Mum, because she never rings when she’s at work.

I’m not sure what’s in this cake. It ___ be coconut.

I’m going to buy this book. I think it ___ help with my school project. 

2 Complete the second sentence so that it means the same as the first.

I’m sure Dad’s tired. He’s been at work all day. =

Dad ___ be tired. He’s been at work all day.

I’m not sure but it looks like snow falling outside. =

It _________________ be snow falling outside. 

Karl isn’t asleep – he’s singing upstairs in his room. =

Karl _________________ be asleep. He’s singing upstairs in his room!

I don’t know who’s in this photo – maybe Ted’s family? =

It _________________ be Ted’s family in the photo. 

I’m sure my bag’s on the table. I left it there! =

My bag _________________ be on the table – I left it there! 

Who’s the person with Billy? Perhaps it’s his sister. =

The person with Billy _________________ be his sister.