瑞氏染色法的染色原理（）。 A.物理吸附 B.化学亲和 C.物理吸附和化学亲和 D.

用下列单词的适当形式填空。

strike, beat, hit 

1. The criminal gang _____ the man so severely that he almost died.

2. I left immediately after the clock _____ twelve.

3. _____ while the iron is hot.

4. What _____ me was their enthusiasm for work.

将a mol 铜加入到一定浓度的硝酸溶液中，充分反应后，铜完全溶解并产生气体（不考虑N₂ O₄ ）．试回答下列问题：

（1）硝酸在该反应中表现的性质为______．

（2）当a=0.2 时，则反应中转移的电子数为______mol，若此时收集到的气体在标准状况下的体积为4.48L，则该气体为______．

（3）用NH₃吸收硝酸生产中产生的尾气是一种较为先进的处理方法，其产物是参与大气循环的物质，对环境无污染，目前在工业生产中已被广泛应用．试写出用NH₃恰好吸收（2）所产生气体的总化学方程式______．

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There are advantage for students to work while                                      1.       

studying at school.One of them was that                                                       2.       

they can earn money.For the most part,                                                        3.       

students working to earn money for their own                                               4.       

use.Earning their own money allow them                                                      5.       

to spend on anything as if they please.                                                                6.       

They would have to ask their parents for                                                       7.       

money or for permission to do things by                                                       8.       

the money.Some students may also to save                                                    9.       

up for our college or future use.                                                                  10.       

红细胞异常结构包括()

A．豪焦小体

B．卡波环

C．杜勒小体

D．嗜碱性点彩颗粒

E．嗜多色性红细胞

局限性青少年牙周炎好发牙是（）。

A．上颌切牙

B．下颌切牙

C．前磨牙和上下切牙

D．第一磨牙和上下切牙

E．第二磨牙和上下切牙