__________ do you exercise every day? 　　　　—More than an hour. 　　[ ]

Who’s that? —My aunt. ________ is a nurse in a hospital.

Many scientists say that it’s important for us to have ______ food in our diet.

The plane will take off _______ three hours. I must get to the airport right now. [ ]

Everyone knows that China is famous _____ the Great Wall in the world.[ ]