甲生物核酸的碱基组成为:嘌呤占46%、嘧啶占54%,乙生物遗传物质的碱基比例为:嘌呤

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问题:

甲生物核酸的碱基组成为:嘌呤占46%、嘧啶占54%,乙生物遗传物质的碱基比例为:嘌呤占34%、嘧啶占66%,则甲、乙生物可能是()

A.蓝藻、变形虫

B.T2噬菌体、豌豆

C.硝化细菌、绵羊

D.肺炎双球菌、烟草花叶病毒

考点:高中生物DNA的结构与复制DNA的结构与复制题库
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患者,女,45岁,葡萄胎刮宫术后,预防性切除子宫。病理检查子宫肌层内有水泡状组织,镜下见增生的滋养细胞及绒毛结构,应诊断为

A.侵蚀性葡萄胎

B.绒癌

C.子宫肌腺瘤

D.葡萄胎

E.子宫内膜炎

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若公司最近2年连续亏损,交易所可暂停其可转换公司债券上市。( )

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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.

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每个服务群组号可以容纳()个终端类型的节点。

A.128

B.256

C.512

D.1024

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()是导致心理和躯体障碍的一个重要因素。

A、缺乏安全感

B、身心疲惫

C、亚健康

D、缺乏社会支持

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