问题 单项选择题

美国科学家理查德·阿克塞尔和琳达·巴克发现,当气味分子与嗅觉受体结合后,作为化学信号的气味分子经过属于GTP结合蛋白(通称G蛋白)的嗅觉受体的复杂作用,转变为电信号后,便沿着嗅觉神经开始一场接力跑。这些信号先从鼻腔进入颅内,最后被传至大脑嗅觉皮层某些精细区域,在那里它们被翻译成特定的嗅觉信息,即被人们感知。
这段文字主要谈的是( )。

A.阿克塞尔和巴克所描述的嗅觉信号通路理论
B.嗅觉信号通路的末端是大脑嗅觉皮层中的某些精细区域
C.嗅觉信号通路理论阐述的是气味分子转化为嗅觉信号传递到大脑的过程
D.作为化学信号的气味分子到达大脑嗅觉皮层某些精细区域被翻译成嗅觉信息

答案

参考答案:A

解析: 该段文字主要是对嗅觉信号通路理论的描述,B、C、D三项只是其中的一部分,故只有A项最全面。

单项选择题
阅读理解

阅读理解。

     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're

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 for an answer, no time for a

child to think. When adults increase their "wait time" to three seconds or more, children give

more logical(符合逻辑) , 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 t9. 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 (放大镜), and they' II understand why you want them to wash before

 dinner. Rather than saying that water evaporates (蒸发) , set a pot of water to boil and let them

watch the water level drop.

1. According to the passage, children are natural scientists, and to raise their interest, the most important

thing for adults to do is ______.

A. to let them see the world around  

B. to share the children's curiosity

C. to explain difficult phrases about science            

D. to supply the children with lab equipment

2. 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

3. According to the passage, children can answer questions in a more logical, complete and creative way

if adults ______.

A. ask them to answer quickly

B. wait for one or two seconds after a question

C. tell them to answer the next day

D. wait at least for three seconds after a question

4. The author mentions all of the following techniques for adults to share with their children's curiosity

except that adults should ______.

A. tell their children stories instead of reciting facts

B. offer their children chances to see things for themselves

C. be patient enough when their children answer questions

D. encourage their children to ask questions of their own