spects of a pilot’s job__________ beboring, and pilots often ________ work at inconvenient hours

We shall go to help them_______we are free.

past several weeks, many cities in NorthernChina from heavy fogs and severecold.

What did you do in today’s history class-We talked about the characters____ achieved fame in American history.

The present situation is very complex,so I think it will take me some time to_____ its reality.[ ]