用亚甲基蓝比色法测定空气中硫化氢时，加入混合显色液后放置30分钟，再加磷酸氢二钠溶液

在制气过程中，风机能力大、优质原料，粒度大而均匀及炭层阻力小时，宜采用高炭层的操作条件。

阅读理解。

     When a rather dirty, poorly dressed person kneels at your feet and puts out his hands to beg for a few

coins, do you hurry on, not knowing what to do, or do you feel sad and hurriedly hand over some money?

What should our attitude to beggars be? There can be no question that the world is full of terribly sad

stories. It must be terrible to have no idea where our next meal is going to come from. It seems cruel not

to give some money to beggars.

     Certainly, most of the world's great religions (宗教) order us to be open-hearted and share what we

have with those less fortunate than ourselves.But has the world changed? Maybe what was morally (道德

方面) right in the old days,when one knew exactly who in the village had suffered misfortune and needed

help,is no longer the best idea. Quite a few people will not give to beggars. Let us look at their arguments.

     First, some believe that many city beggars dress up on purpose to look pitiable and actually make a good

living from begging. Giving to beggars only encourages this sort of evil (恶行). Secondly, there is the worry

that the money you give will be spent on beer, wine or drugs.Thirdly,there is the opinion that there is no real

excuse for begging. One might be poor,but that is no reason for losing one's sense of pride and

self-dependence.

     Related to this is the opinion that the problem should be dealt with by the government rather than ordinary

people. Some people think beggars should go to the local government department and receive help.

     It is hard to come to any final conclusion; there are various cases and we must deal with them differently.

A few coins can save a life in some situations, and even if the money is wasted, that does not take away the

moral goodness of the giver.

1. What is mainly discussed in the passage?

A. Moral deeds of people.

B. Religious activities of the church.

C. Moral goodness of the giver.

D. Arguments on giving to beggars.

2. What can we infer from the sentence "But has the world changed?" in the second paragraph?

A. People no longer know who suffers misfortune in the village.

B. Some people will not do what was morally right in the past.

C. We don't meet with those who need help any more.

D. Now it is the government's duty to help the beggars.

3. Which of the following is NOT mentioned in the passage?

A. Some people dress up to pretend to be beggars.

B. Some beggars want money to help their children go to school.

C. Some beggars use the money to buy drugs.

D. Some beggars have no excuse for begging.

4. In the last paragraph,the writer thinks that it is hard to come to any final conclusion, because _____.

A. the cases can be so different

B. there are so many beggars

C. there is so much money wasted

D. there are so many different arguments

结构实体检验采用由各方参与的见证抽样形式，以保证检验结果的公正性（）

有性世代

淬火后的钢重新加热到低于A1的某一选定温度并保持一定时间，然后以适当的速度冷却的热处理工艺叫（）。

A.渗碳

B.正火

C.退火

D.回火