有关二尖瓣狭窄的血流动力学改变，下列哪项是错误的（） A.肺毛_爱下问搜题

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问题单项选择题

有关二尖瓣狭窄的血流动力学改变，下列哪项是错误的（）

A.肺毛细血管压力增高

B.左心房压力增高

C.左心室肥大

D.肺动脉高压

E.血流经二尖瓣口时跨瓣压差增加

答案

参考答案：C

解析：二尖瓣狭窄时由于左心房排血受阻，房压升高，肺静脉和毛细血管淤血，压力升高，肺动脉也可由于肺小动脉管壁增厚、狭窄而压力显著增高。此时，左心室处于相对少血状态。

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.

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

判断题

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