【多选题】
横桥的特性是：
A. 可与肌纤蛋白结合，拖动细肌丝向M线方向滑行
B. 可与肌钙蛋白结合，使原肌凝蛋白分子构型发生改变
C. 具有ATP酶活性
D. 具有腺苷酸环化酶活性
E. 具有GTP酶性
查看试卷，进入试卷练习
微信扫一扫，开始刷题
答案
AC
解析
暂无解析
相关试题
【多选题】
固定前负荷，改变后负荷对肌肉收缩的影响是：
A. 后负荷加大时，可使肌肉收缩的张力增大，缩短速度变慢
B. 后负荷加大到一定程度，可使肌肉出现等长收缩
C. 后负荷减小到零时，肌肉收缩的缩短速度达到最大值
D. 只要有后负荷，总是缩短出现在前，张力产生在后
E. 肌肉收缩时，总是张力产生在前，缩短产生在后
【多选题】
前负荷对肌肉收缩的影响表现为：
A. 前负荷加大时，肌肉最大张力随之加大
B. 加大到超过最适前负荷时，肌肉最大张力随之减小
C. 最适前负荷可使肌肉产生最佳收缩效果
D. 最适前负荷使肌肉处于最适初长度
E. 只要有前负荷，总是缩短出现在前，张力产生在后
【单选题】
推进气体进出肺的直接动力是：___
A. 肺内压与大气压之间的压力差
B. 肺内压与胸膜腔内压之间的压力差
C. 胸膜腔内压与大气压之间的压力差
D. 肺内压与跨壁压之间的压力差
E. 胸膜腔内压的周期性变化
【单选题】
以下叙述错误的是___。
A. 机体与环境之间的气体交换过程称为呼吸
B. 呼吸由外呼吸、气体在血液中的运输、内呼吸组成
C. 生理条件下，胸膜腔内压均高于大气压
D. 胸膜腔负压可以维持肺扩张、有利于静脉血和淋巴液的回流
E. 机体在新陈代谢中需要不断的吸入氧气、排出二氧化碳
【单选题】
对肺弹性阻力的叙述，错误的是___
A. 肺弹性阻力包括肺泡表面张力所产生的回缩力
B. 肺组织本身的弹性阻力主要来自弹性纤维
C. 肺组织本身的弹性阻力约占肺总弹性阻力的2/3
D. 肺弹性阻力大小一般用肺顺应性来表示
E. 肺弹性阻力与肺顺应性成反变关系
【单选题】
肺的顺应性变大可由于___
A. 肺泡表面张力增加，弹性阻力变小所致
B. 肺泡表面张力减小，弹性阻力变小所致
C. 肺跑表面张力增加，弹性阻力增大所致
D. 肺泡表面张力减小，弹性阻力增大所致
E. 以上都不对
【单选题】
肺泡表面活性物质：___
A. 由肺泡Ⅰ型细胞分泌
B. 分布于肺泡液体分子层与肺泡上皮细胞之间
C. 主要成分是二硬脂酰卵磷脂
D. 能增加肺泡表面张力
E. 能增加肺顺应性
【单选题】
关于肺泡表面活性物质的叙述，错误的是___。
A. 由肺泡Ⅱ型细胞合成和分泌的
B. 可减小肺的弹性阻力
C. 使肺扩张，保证肺通气
D. 防止肺水肿的发生
E. 可增大肺泡表面张力
【单选题】
大小肺泡稳定性的维持，有赖于肺泡表面物质在：___
A. 大肺泡内密度低，小肺泡内密度高
B. 大肺泡内密度高，小肺泡内密度低
C. 大小肺泡内密度均高
D. 大小肺泡内密度低
E. 大小肺泡内密度于呼吸周期中随机变化
【单选题】
关于肺通气阻力的描述，错误的是___
A. 肺通气阻力来自弹性和非弹性阻力
B. 弹性阻力来自肺组织和胸壁
C. 非弹性阻力主要来自呼吸道气流的摩擦
D. 同样压力下，弹性阻力大则表示顺应性也大
E. 肺的顺应性过分减小或过分增大，对呼吸均不利
【单选题】
进入肺泡内的气体，可因血液在肺内分布不均而未全部与血液进行气体交换。没有发生气体交换的这部分肺泡容量，称为___
A. 解剖无效腔
B. 生理无效腔
C. 肺泡无效腔
D. 气道无效腔
E. 无效腔
【单选题】
肺泡通气量是指___。
A. 每分钟吸入的气体量
B. 每分钟呼出的气体量
C. 每分钟吸入肺泡的新鲜气量
D. 尽力呼吸时，每分钟吸入的最大气体量
E. 肺泡通气量=（潮气量+无效腔气量）×呼吸频率
推荐试题
【单选题】
( ) 40. The best title of the passage is ___________.
A. Rivers in Cities B. The importance of Rivers
C. Transportation D. Natural Resources
A. A
B. B
C. C
D. D
【单选题】
) 1. Even Tony’s six-year-old son asked him ______ smoking.
A. stops B. stopped C. to stop D. stopping
A. A
B. B
C. C
D. D
【单选题】
2.—What do you think of the lecture of Li Yang’s Crazy English?
— I think it’s _______ , but someone thinks it’s much too ________.
A. wonderful enough; bored B. enough wonderful; boring
C. enough wonderful; bored D. wonderful enough; boring
A. A
B. B
C. C
D. D
【单选题】
3.—He didn’t go to the lecture this morning, did he?
— _____ ．Though he was not feeling very well．
A. No, he didnt B. Yes; he did C. No, he did D. Yes, he didnt
A. A
B. B
C. C
D. D
【单选题】
4. If you read a lot, your life ______ full of pleasure.
A. will be B. is C. be D. was
A. A
B. B
C. C
D. D
【单选题】
5. The black bag _________ be Annas. She has a blue one.
A. should B. cant C. wouldnt D. could
A. A
B. B
C. C
D. D
【单选题】
6. Susan, why are you still here? They are all ready to start.
Im sorry, but I _________ when to start.
A. dont tell B. wasnt told C. didnt tell D. havent told
A. A
B. B
C. C
D. D
【单选题】
7.—Why dont you choose the red tie?
—For me, it doesn’t _____ my shirt very well．
A. fix B. accept C. compare D. match
A. A
B. B
C. C
D. D
【单选题】
8. — Could you tell me ______? I must find him．
— Sorry．I don’t know．But he was here just now．
A. where Tom was B. where Tom is
C. where has Tom gone D. where can I find Tom
A. A
B. B
C. C
D. D
【单选题】
9. —What did Mr Green say to you?
— What a heavy rain! How did you come here? He asked________.
A. at all B. in fact C. in surprise D. as a result
A. A
B. B
C. C
D. D
【单选题】
10. I often see Tom on the playground．When I passed the playground yesterday, I saw him ．
A. play; playing B. to play; play C. playing; to play D. playing; play
A. A
B. B
C. C
D. D
【单选题】
11. — Mum, could I have ____________ to drink?
— Oh, dear．You can only drink some water．There is _________ in the kitchen．
A. anything; else something B. anything; something else
C. something; else nothing D. something; nothing else
A. A
B. B
C. C
D. D
【单选题】
12. We all know that learning a foreign language _______ time and effort.
A. requires B. reduces C. removes D. repeats
A. A
B. B
C. C
D. D
【单选题】
13. Her son __________ Coke, but now he __________ milk．
A. is used to drinking; used to drink B. used to drink; uses to drink
C. used to drink; is used to drinking D. is used to drink; is drinking
A. A
B. B
C. C
D. D
【单选题】
14. I don’t know the teacher is talking with Miss Wang．
A. what B. whom C. who D. which
A. A
B. B
C. C
D. D
【单选题】
15.Millie does __________ that many people are thankful to her．
A. such an important and helpful job B. so important and helpful work
C. a very important and helpful job D. such an important and helpful work
A. A
B. B
C. C
D. D
【单选题】
16. I think eating more vegetables is good _______ our health.
—Yes, I agree _______ you.
A. at, to B. for, with C. to, to D. for, to
A. A
B. B
C. C
D. D
【单选题】
17. I often go on holiday with my parents _____ summer.
A. in B. at C. on D. of
A. A
B. B
C. C
D. D
【单选题】
18. I called you at 4:00 yesterday afternoon, but nobody answered.
Sorry, I ______ with my friends at that time.
A. had swum B. swam C. would swim D. was swimming
A. A
B. B
C. C
D. D
【单选题】
19.––Who is on the playground? ---__________．
A. Never B. None C. No one D. A lot
A. A
B. B
C. C
D. D
【单选题】
20. The schoolboy ______ a blind man cross the street yesterday.
A. helps B. helped C. will help D. has helped
A. A
B. B
C. C
D. D
【单选题】
21. —The 2010 World Expo which will last 184 days will be held in Shanghai on May 1st.
—________exciting news! We shall try our best to support it.
A. How B. How an C. What D. What an
A. A
B. B
C. C
D. D
【单选题】
22. They preferred ______ in bed rather than _____ horses．
A. to lie; to ride B. lying; riding C. lying; ride D. to lie; ride
A. A
B. B
C. C
D. D
【单选题】
23. —What was Jim wearing at the party?
— Nothing _______. He was in his usual shirt and jeans.
A. special B. simple C. important D. interesting
A. A
B. B
C. C
D. D
【单选题】
24. The 2016 Olympic Games ________ in Brazil. Would you like to go there?
Maybe, if possible.
A. are held B. will be held C. were held D. have been held
A. A
B. B
C. C
D. D
【单选题】
25. — David, look at the man in white over there．Can you tell me _______ ?
—He is a doctor．
A. who is he B. who he is C．what does he do D. what he does
A. A
B. B
C. C
D. D
【单选题】
( ) 26.With help from a Mr. H, you can__________.
A. stop wearing your watch B. get new books and objects
C. finish your homework on time D. know when parents or teachers are near
A. A
B. B
C. C
D. D
【单选题】
( ) 27. A PENGO WATCH CONTROL can help you to ______________.
A. repair your TV B. put away your books and objects
C. become a James Bond D. get a daily weather report
A. A
B. B
C. C
D. D
【单选题】
( ) 28. You can get your Mr. H for___________.
A. $299 B. $499 C. $199 D. $99
A. A
B. B
C. C
D. D
【单选题】
( ) 29. When was canned food invented?
A. In 1870. B. In 1810. C. In 1902. D. In 1926.
A. A
B. B
C. C
D. D
【单选题】
( ) 30. After the trip to the Arctic, Clarence Birdseye invented ____________.
A. canned food B. can openers
C. frozen food D. air conditioning
A. A
B. B
C. C
D. D
【单选题】
( ) 31. Changes in weather _____________ in Willis Carrier's company.
A. helped to keep food B. made rooms comfortable
C. caused health problems D. hurt printing paper
A. A
B. B
C. C
D. D
【单选题】
( ) 32. According to the passage, which of the following may lead to inventions?
A. People's needs. B. Public support.
C. Modern technology. D. Practical suggestions.
A. A
B. B
C. C
D. D
【单选题】
( ) 33. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
A. A
B. B
C. C
D. D
【单选题】
( ) 34. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
A. A
B. B
C. C
D. D
【单选题】
( ) 35. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
A. A
B. B
C. C
D. D
【单选题】
( ) 36. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
A. A
B. B
C. C
D. D
【单选题】
( ) 37. The Chinese Yellow Sea Wetlands are in the _______ of China．
A．south B．east C．west D．north
A. A
B. B
C. C
D. D
【单选题】
( ) 38. Usually the weather in the wetlands is _______．
A．hot B．pleasant C．cold D．dry
A. A
B. B
C. C
D. D
【单选题】
( ) 39. The World Wetlands Day is on _______．
A．February 2 B．June 25 C．April 22 D．March
A. A
B. B
C. C
D. D
