与描述性和分析性研究相比，流行病学实验具有以下特点（） A.必

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问题多项选择题

与描述性和分析性研究相比，流行病学实验具有以下特点（）

A.必须有干预措施

B.是实验方法而非观察性方法

C.实验的性质是回顾性的

D.须随机化分组

E.实验组与对照组是自然形成的

答案

参考答案：A, B, D, E

听力题

用所给词的适当形式填空(10分)

小题1:The English teacher told us that we had a (month) test on each subject.

小题2:Just now more than one criminal ___________(arrest) by the police.

小题3:Audrey Hepburn was not only beautiful but also (experience).

小题4:With the help of the computer, the spacemen can be sent to the space even (safe).

小题5:Tom, (put) up a drawing of the panda on the wall tomorrow.

小题6:Fights in action films (they) have a bad effect on teenagers, don’t they?

小题7:The bad air makes my head hurt and it’s difficult for me __________(breath).

小题8:—Did Amy come (twelve) in the girls’ 400-metre race? —Yes.

小题9:—What about hiding those __________(enemy) guns behind the tree? —Good idea.

小题10:The host said that the results _________ (announce) the following day.

名词解释

水击现象