Modal verbs

You ... believe how scared I've been!

If something ... make you smile, I'd like to know what it is.

We just do what ... to be done, don't we?

Maybe, we ... have a party or something.

You ... expect me to think it's a very good system.

... I offer you some fruit?

To succeed one ... do something.

We ... go as quickly as we can.

It ... be nice to be famous.

The boy ... be thirty by now.

You ... to do it.

How long did you ... to stay here?

Someone ... to go for a doctor.

I simply ... imagine what he meant.

They ... come tomorrow.

We ought to give Mary a lift, ... we?