1.We should give what a child has done a proper prize.
这句话的从句是what a child has done...因为a child has done缺少宾语,所以用What来充当done的宾语,意思是这个孩子做了什么.
2.People in Chongqing are proud of what they have achieved in the past ten years.
从句是what they have achieved...跟上一题一样,what在从句里充当achieve的宾语.they have achieved what.
3.We all expect that they will win.
这句话的从句是that后面的 they will win.
they will win这句话已经很完整了,主语是they,谓语是will,宾语是win.主谓宾都存在了,所以不需要用what来充当任何成分.