一项系统评价综合可25篇应用口服阿司匹林预防冠心病的随机对照试验结果：实验组冠心病发生率12%，对照组发生率18%。

试验组相对危险降低率为（）。

A.6%

B.50%

C.33.3%

D.15%

E.3%

根据汉语或首字母提示完成句子。

1. Our________ (班长) is very outgoing.

2. Many________(游客) come to visit China every year.

3. I'm________ (累了). I want to have a rest.

4. Last week they t________ the bus back to school.

5. Let's do some o________ activities (活动). They're interesting.