1．The Chinese people should make a greater contribution to mankind(人类)．
2．We know that ice is disappearing and after a while it just becomes a statistic(数据)．
3．They often form along the boundary(边界) between the dune and the surface below.
4．This is useful for bathrooms or any surface you desire to disinfect．
5．What do you mean have I been drinking? You are the trained specialist．
6．It's vital we are as fresh as possible for those matches.
7．He assisted the professor in compiling the dictionary.
