在临床医学研究中，对待受试者的正确做法是（）

A.对受试者的负担不可以过分强调

B.对受试者的受益要放在首要位置考虑

C.对受试者的负担和受益要公平分配

D.需要特别关照参加试验的重点人群的利益

E.对参加试验的弱势人群的权益可以不必太考虑

用所给动词的适当形式填空。

1. Hello, I _____ (not know) you _____(be) in London. How long have you been

there?

2. By the end of last week, he _____(read) this book four times.

3. I _____ (not have) any English knowledge before I came here.

4. I _____(lose) my keys. I can't remember where I last saw them.

5. －_____you _____ (see) the film yet'?

    －Yes, I _____(see) it last week.