I think zoos provide clean and safe places endangered animals to live in.[ ]

When _____ the film _____ ? —It _____ for five minutes.

Mr Wang is very strict _____ us. We are afraid _____ him. [ ]

What do you think of the dish? —It is sweet and sour, but isn’t __________.

The doctor ____ the crying baby but couldn’t find out what was wrong with it.