简述污染物几种重要的形态分类。

以下哪项不宜火煅（）

A.代赭石、石膏

B.朱砂、琥珀

C.石决明、珍珠母

D.磁石、礞石

E.牡蛎、龙骨

需求分析的任务是借助于当前系统的物理模型导出目标系统的逻辑模型，解决目标系统“做什么”的问题。（28）并不是需求分析的实现步骤之一。

A．获得当前系统的物理模型

B．抽象出当前系统的逻辑模型

C．建正立目标系统的逻辑模型

D．确定目标实现的具体技术路线

器质性生长激素缺乏症

阅读理解

     I have been very lucky to have won the Noble Prize twice.  It is, of course, very exciting to have such

an important recognition of my work, but the real pleasure was in the work itself. Scientific research is like an exploration of a voyage of discovery. You are continually trying out new things that have not beendone before.  Many of them will lead nowhere and you have to try something different, but sometimes an

experiment does work and tells you something new and that is really exciting.  However small the new

finding may be, it is great to think "I am the only person who knows this" and then you will have the fun of

thinking what this finding will lead to and deciding what will be the next experiment. One of the best things about scientific research is that you are always doing something different and it is never boring. There are

good times when things  go well and bad times when they don't. Some people get discouraged at the

difficult times but when I have a failure, my policy has always been not to worry but to start planning the

nextexperiment, which is always fun.

     It is very exciting to make a new discovery. Some people will do the strangest things for this

excitement, such as going round the world in a balloon or walking to the North Pole. There are not many

new places to explore but there is a lot of new information to be discovered in science and a journey into

this unknown area can be much more worthwhile and just as exciting.

     I'm sometimes asked, "What do you have to do to win a Noble Prize?" My answer is, "I don't know.

I have never tried. " But I know of one way not to win. There are some people whose main reason for

doing science is to win prizes and they are always thinking about how to do it. Such people don't succeed. To do good science you must be interested in it and enjoy doing experiments and thinking out problems.

And, of course, you must be prepared to work hard and not to be too discouraged by failures.

1. In the writer's eyes his greatest pleasure in all his lifetime is        .

A. to win the Nobel Prize for the first time

B. to be awarded the Nobel Prize for the second time

C. in the work itself

D. to have a much more important recogniition of his work

2. Why did the writer think scientific research to be one of the best things?

A. You will be able to win the Nobel Prize through the scientific research.

B. You can make as much money as possible by doing the scientific research.

C. You may continue doing with something different and exciting, and so you can never be

      tired of doing the scientific research.

D. You can get much more chances of promotion(晋级) by making the scientific research.

3. What would the writer do when he had a failure?

A. He would forget this failure and start the next experiment.

B. He used to be womed about it for several days and never forget it.

C. He always gave up his study as the result of the failure.

D. He used to think out the reasons and then continue to do it again.

什么是滑动窗口流量控制协议？举例说明。