成人脊髓的位置()A、上端平枕骨大孔与中脑相连 B、下端成人平齐第一腰椎下缘 C、下端成

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问题:

成人脊髓的位置()

A、上端平枕骨大孔与中脑相连

B、下端成人平齐第一腰椎下缘

C、下端成人平齐第三腰椎下缘

D、下端成人平齐第二骶椎下缘

E、上端与小脑相连

考点:人体解剖学神经系统神经系统题库
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如图,R0为定值电阻,电源电压恒定.闭合开关,当滑动变阻器接入电路的电阻为R/4时,电压表读数为4V;当滑动变阻器接入电路的阻值为R时,电压表的读数为2V,则前后两次通过R0的电流之比______,电源电压______V.

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并指(趾)是由于相邻指(趾)间骨性或软组织融合形成的手足畸形,是人类常见的肢端畸形病。下图表示某家庭先天性并指(趾)遗传系谱,据图回答:

(1)由遗传图解可以看出并指(趾)属于_______染色体_______性遗传病。

(2)Ⅲ4和Ⅲ5婚后孩子正常的几率是_______。若Ⅲ5已经怀孕,为了生一个正常指(趾)的孩子,应该进行________以便确定胎儿是否患病。

(3)研究人员从该家庭多名患者的血液样本中提取DNA进行分析时发现,患者的第2号染色体的HOXD13基因中增加了一段碱基序列:

-CGCCGCCGCCGCCGTCGCCGCCGACGC-(模板链),导致其指导合成的蛋白质中最多增加了_________个氨基酸,并且全是__________。(精氨酸:CGU、CGC、CGA、CGG,丙氨酸:GCU、GCA、GCG、GCC,脯氨酸:CCG、CCA、CCU、CCC)

(4)上述研究表明,并指(趾)是由_______引起的一种遗传病。该家庭中的致病基因主要来自Ⅰ2,由于这种变化发生在______细胞,从而导致每一代都有患者出现。

题型:单项选择题

世界上许多科学家的重大发现和发明,都产生于风华正茂、思维敏捷的青年时期。爱迪生发明留声机时29岁,发明电灯时31岁;牛顿发明微积分时22岁;爱因斯坦提出狭义相对论时26岁,提出广义相对论时37岁;李政道和杨振宁发现弱相互作用下宇称不守恒定律时分别是30岁和34岁。    

上述材料说明了什么道理?青少年应学习他们什么样的精神?

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题型:单项选择题

We might marvel at the process made in every field of study, but the method of testing a person’s knowledge and ability remain as primitive as ever they were. It really is extraordinary that after all these years educationists have still failed to devise anything more efficient and reliable than examinations.
41. ______
They may be a good means of testing memory, or the knack of working rapidly under extreme pressure, but they can tell you nothing about a person’s true ability and aptitude.
42. ______
Your whole future may be decided in one fateful day. It doesn’t matter that you weren’t feeling very well, or that your mother died. Little things like that don’t count: the exam goes on. no one can give of his best when he is in mortal terror, or after a sleepless night, yet this is precisely what the examination system expects him to do. The moment a child begins school, he enters a world of vicious competition where success and failure are clearly defined and measured. Can we wonder at the increasing number of "dropouts": young people who are written off as utter failures before they have even embarked on a career Can we be surprised at the suicide rate among students
43. ______
Examinations do not motivate a student to read widely, but to restrict his reading; they do not enable him to seek more and more knowledge, but induce cramming. They lower the standards of teaching, for they deprive the teacher of all freedom. Teachers themselves are often judged by examination results and instead of teaching their subjects, they are reduced to training their students in exam techniques which they despise. The most successful candidates are not always the best educated; they are best trained in the technique of working under duress.
44. ______
Examiners are only human. They get tried and hungry; they make mistakes. Yet they have to mark stacks of hastily scrawled scripts in a limited amount of time. They work under the same sort of pressure as the candidates. And their word carries weight. After a judge’s decision you have the right of appeal, but not after an examiner’s.
45. ______
Is it cynical to suggest that examinations are merely a profitable business for the institutions that run them This is what it boils down to in the last analysis. The best comment on the system is this illiterate message recently scrawled on a wall: "I were a teenage drop-out and now I am a teenage millionaire."
[A] A good education should, among other things, train you to think for yourself. The examination system does anything but that. What has to be learnt is rigidly laid down by a syllabus, so the students are encouraged to memorize.
[B] The results on which so much depends are often nothing more than a subjective assessment by some anonymous examiner.
[C] Examinations can be taken as a test of a student’s knowledge about a particular subject which would tell the student where he stands among others, and how much he knows and how much he ought to know.
[D] As anxiety-makers examinations are second to none. That is because so much depends on them. They are the mark of success or failure in our society.
[E] The student appearing for the exam takes it under extreme tension and pressure because he knows that he has only one chance to prove his worth and if he fails, he will be left behind for the rest of his life.
[F] For all the pious claim that examinations test what you know, it is common knowledge that they more often do the exact opposite.
[G] There must surely be many simpler and more effective ways of assessing a person’s true abilities.

题型:单项选择题

开胸后出现病理呼吸是()

A.摆动呼吸

B.成串呼吸

C.反常呼吸

D.失调呼吸

E.长吸呼吸

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