网上银行判别注册客户合法性身份和确认交易有效性的标识是（）。A.客户证书 B.银行卡

一个袋子中装有2个红球和2个绿球，任意摸出一球，记录颜色放回，再任意摸出一个球，记录颜色后放回，请你求出两次都摸到红球的概率．

根据句意及首字母提示补全单词，使句意完整。

1. Look at the map, can you s_____ China on it?

2. A panda (熊猫) is b_____ and w_____.

3. W_____ to our store.

4. He can't a_____ a new house.

5. He w_____ a yellow car.

6. There are many clothes on s_____.

7. You must do your things y_____.

8. I can't work out the math problem (问题), could you give me an e_____?

9. The store has shoes at a very good p_____.

10. E_____ of the students in our class has an English dictionary.

中药配伍的目的是（）。

A.增强疗效

B.减轻毒性

C.扩大治疗范围

D.适应复杂病情

E.改变药物的味

肠外营养的并发症不包括哪一项（）。

A.空气栓塞

B.高血糖

C.低血糖

D.不利切口愈合

E.微量元素缺乏

第一心音和第二心音在心脏哪个部位听诊最清晰？