Bill overslept this morning. He might have worked late.
Past
Where are they? They could have got lost.
Past
They might be at home.
Present
If we don't hurry, we could be late.
Present
They hadn't eaten all day. They must have been hungry.
Past
That dog could be dangerous.
Present
They might have left while he was sleeping.
Past
It could be very cold there in winter.
Present
A: Where's John? B: I'm not sure. He might be in the canteen.
Present
You look happy. You must have heard the good news.
Past
She doesn't know the city well. She could have taken the wrong bus.
Past