I’m afraid I can’t return the book to you before Friday.—_______.

When I got to the cinema, the movie ___for 15 minutes.

Where did you come across our chemistry teacher ?—— It was in the supermarket ______ I purchased mooncakes.

I’ll telephone you as soon as Tom ________ here.

The disappearance of dinosaurs is not necessarily caused by astronomical incidents. But _________explanations are hard to find.