(2009年合肥市高三第一次教学质量检测)He sighed again and the failure in physics seemed to have completely his confidence．

The number of people ________ this happens isnot very large.

My mother has a backache in hospital —_________________.

The enemies tried to ____ the city, but they failed in the end.

If the children are going to camp for two weeks by themselves,they’ll need to know the ____ knowledge of taking care ofthemselves.[ ]