It’s hard for the young people to imagine what _____ conditions their parents once lived under.

The doctor suggested he________food which is rich ________fat and sugar. [ ]

Where is my English dictionary, Mum—It ______ away by your sister yesterday.

当别人对你说：＂Sit down, please. (请坐)＂时，你应该说 ____________.

It’s difficult to ___ these old books for some of them ______ none of the classification.