关于宾语从句的练习

能给分的话就太谢谢了.
1 what he lost at the station.
2 (should be )where the accident happened.
3 what foreign language you can speak
4 whose box it is on the floor.
5 who discovered the area.
6 if the engineer knew French.
1 We must find out the reason why the car caught fire yesterday.
2 This foreign guest wants to know how China brings out the education reform.
3 Do you know which house they would like to buy?
4 We are sure that the Chinese athletes will achieve great successes on the Olympic Games Meeting.
5 I was moved by this blind young man's own life story which had been told by himself.