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问题 选择题

无硫火柴逐渐取代了含硫火柴的主要原因是：含硫火柴燃烧后能产生一种大气污染物，该气体为（　　）

A．二氧化硫

B．二氧化碳

C．二氧化氮

D．一氧化碳

答案

含硫火柴中的硫燃烧会生成二氧化硫气体，二氧化硫无色有刺激性气味，是大气污染物之一，与水反应会生成酸雨，对建筑物、植物等造出很大危害．

故选A．

单项选择题

Passage Two


Children start out as natural scientists, eager to look into the world around them. Helping them enjoy science can be easy ;there’s no need for a lot of scientific terms or expensive lab equipment. You only have to share your children’s curiosity. Firstly,listen to their questions. I once visited a classroom of seven-year-olds to talk about science as a job. The children asked me" textbook questions" about schooling, salary and whether I liked my job. When I finished answering, we sat facing one another in silence. Finally I said, "Now that we’ve finished with your lists, do you have questions of your own about science"
After a long pause ,a boy raised his hand," Have you ever seen a grasshopper(蚱蜢) eat When I try eating leaves like that, I get a stomachache. Why"
This began a set of questions that lasted nearly two hours.
Secondly, give them time to think. Studies over the past 30 years have shown that, after asking a question, adults typically wait only one second or less tor an answer, no time for a child to think. When adults increase their" wait time" to three seconds or more, children give more logical, complete and creative answers.
Thirdly, watch your language. Once you have a child involved in a science discussion, don’t jump in with" That’s right" or" Very good". These words work well when it comes to encouraging good behavior. But in talking about science, quick praise can signal that discussion is over. Instead, keep things going by saying" That’s interesting" or" I’d never thought of it that way- before", or coming up with more questions or ideas.
Never push a child to" Think". It doesn’t make sense, children are always thinking, without your telling them to. What’s more, this can turn a conversation into a performance. The child will try to find the answer you want, in as few words as possible, so that he will be a smaller target for your disagreement.
Lastly, show;don’t tell. Real-life impressions of nature are far more impressive than any lesson children can learn from a book or a television program. Let children look at their fingertips through a magnifying glass, and they’ll understand why you want them to wash before dinner. Rather than saying that water evaporates, set a pot of water to boil and let them watch the water level drop.

In the last sentence of the first paragraph, the word " lists" could best be replaced by______.

A．any questions

B．any problems

C．questions from textbooks

D．any number of questions
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单项选择题

七开间的古建筑最中间的开间称为（）。

A.尽间

B.稍间

C.次间

D.明间
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