Possibilities

Look! What's that? It can't be a plane.

I can't find my keys.

Someone was at the door a few minutes ago.

She must be his girlfriend.

Who's that sitting next to Andrew?

Someone's left their umbrella here.

I'm starving! Is there anything to eat?

Eddie was very quiet this morning.

I can't read this signature – can you make anything of it?

That's the doorbell. Do you think they're here already?

Do you think Gran's alright? She's not answering her phone.

Happy birthday! Can you guess what it is?

It might be Laura's. She was in here earlier.

It's flying too low.

You can't be hungry again! You've only just had lunch.

It must be his dad. He looks just like him.

He must have been tired – he flew back from London last night.

She might be having a nap. She often does after lunch

It must have been the postman. He always comes at eight.

The surname could be Smith. That looks like an 's'.

Look, they're holding hands.

You might have left them at work.

It can't be a book - it's not heavy enough. Is it a video game or a DVD?

They can't be. They only left ten minutes ago and it takes an hour.