The teacher gave the books to all the students except       who had already taken them.

Someone knocked at your door just now,but I didn’t see who     was.

I asked for some more cake, but there was               left.

September 18th, 1931 is a special day, ________， I think, that will be remembered by the Chinese forever.

We have two kinds of summer camps for your holidays. You can choose ______ based on your own interests.