【单选题】
确定正弦量的三要素为 ___。
A. 相位、初相位、相位差
B. 最大值、频率、初相角
C. 周期、频率、角频率
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答案
B
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相关试题
【单选题】
额定电压都为220V的40W、60W、100W三灯泡串联在220V的电源中，它们的发热量由大到小排列为___
A. 100W 60W 40W
B. 40W 60W 100W
C. 100W 40W 60W
D. 60W 100W 40W
【单选题】
已知电源电压为12 V ,四只相同灯泡的工作电压都是6 V，要使灯泡都能正常工作，则灯泡应___
A. 全部串联
B. 两只并联后与另两只串联
C. 两两串联后再并联
D. 全部并联
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【单选题】
According to the passage, we know that Britain______________. ___
A. will adopt lie detectors widely
B. will adopt lie detectors on a smaller scale
C. adopt lie detectors
D. has not decided whether to adopt lie detectors or not
【单选题】
The tests themselves are by no means free from error..." (Line 1-2.Para.3) means ____________. ___
A. the tests definitely have no error
B. the tests sometimes make mistakes
C. the polygraphers do not make mistakes
D. the polygraphers can avoid error by using some techniques
【单选题】
Which of the following is true? ________________ ___
A. The tests are conducted by qualified polygraphers.
B. Innocent people may blush or stammer when questioned.
C. Guilty people can definitely be found out by answer questions
D. Guilty people may escape by refusing to answer questions.
【单选题】
What troubles lie detector researchers most is that _______________. ___
A. innocent people are convicted crimes
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C. lie detectors may cause industrial unrests
D. lie detectors are sometimes not dependable
【单选题】
In the passage the author's attitude towards "mixed-ability teaching" is _______. ___
A. critical
B. questioning
C. approving
D. objective
【单选题】
By "held back" (Line 1) the author means _____. ___
A. made to remain in the same classes
B. forced to study in the lower classes
C. drawn to their studies
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【单选题】
The author argues that a teacher's chief concern should be the development of the student's _________. ___
A. personal qualities and social skills
B. total personality
C. learning ability and communicative skills
D. intellectual ability
【单选题】
Which of the following is NOT MENTIONED in the third paragraph? __________ ___
A. Group work gives pupils the opportunity to learn to work together with others.
B. Pupils also learn to develop their reasoning abilities.
C. Group work provides pupils with the opportunity to learn to be capable organizers.
D. Pupils also learn how to participate in teaching activities.
【单选题】
The author's purpose in writing this passage is to ______. ___
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【单选题】
According to the author, the deaths among youth are mainly caused by _____. ___
A. traffic accidents
B. smoking-related diseases
C. murder
D. all of these
【单选题】
Every day there are over_____high school students who will become regular smoker. ___
A. 75
B. 23
C. 30
D. 3000
【单选题】
By "dropout" the author means______. ___
A. students who failed the examination
B. students who left school
C. students who lost their way
D. students who were driven out of school
【单选题】
The reason for declining adolescent smoking is that ________. ___
A. NCI has taken effective measures
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C. there are many smokers who have died of cancer
D. not stated
【单选题】
What is implied but not stated by the author is that ________. ___
A. smoking rates among youth have declined very little
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【单选题】
According to the passage, which of the following is NOT a disadvantage of part time education? _______________ ___
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C. It affects one's career.
D. It gives the student less time to share with the family.
【单选题】
Which of the following is NOT an advantage of distance learning? _________ ___
A. The student may choose his or her own pace.
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C. They can pursue their chosen career while studying.
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【单选题】
What benefit will distance learning program bring to a business? __________ ___
A. Recruitment of more talented people.
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D. Further training of employees and business growth.
【单选题】
Good distance learning program have the following characteristic EXCEPT______. ___
A. distance learning course is the same as students taking courses in campus
B. the degree should be same as on campus study
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【单选题】
What benefit will distance learning bring to an employee of a business? ___________ ___
A. Professional growth.
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【单选题】
In the first paragraph, what does "plastic money" (Line 6, Para.1) refer to? ______ ___
A. Dollars.
B. Online payment.
C. Credit cards.
D. Coins.
【单选题】
Which of the following is NOT true about credit cards? ____________ ___
A. Shopkeepers, among others, object to the use of credit cards because they add on the cost of the merchandise.
B. Credit card holders actually pay for their goods after the purchase has been completed.
C. The national company enjoys extensive growth because of the use of credit cards.
D. It has had the effect of increasing consumption.
【单选题】
What is the disadvantage of credit cards? _____________ ___
A. It may lead to the overgrowth of the national economy.
B. The delay in the payment of shopping goods may bring damage to shopkeepers' profits.
C. Some people may intentionally purchase goods that they cannot possibly afford.
D. Those who pay by cash at the purchase will have to pay for the cost added to the product as the interest charge of credit cards.
【单选题】
What is the main topic of the text? ________________ ___
A. Advantages and Disadvantages of Credit Cards.
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C. It can encourage great sums of consumption.
D. Credit Cards Make Life
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【单选题】
The author's attitude towards credit card is.______________. ___
A. agreeable
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在甲午战争后，严复翻译的《天演论》所宣传的重要思想是___。
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C. “天下兴亡，匹夫有责”
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【单选题】
鸦片战争以清政府的失败而告终。1842 年 8 月 29 日，清政府与英国签订了中国近代史上的第一个不平等条约是___。
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【单选题】
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下面表述不正确的是___。
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魏源在其___中，提出了“师夷长技以制夷”的思想，主张学习外国先进的军事和科学技术，以期富国强兵，抵御外国侵略，开创了中国近代向西方学习的新风。
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C. 《夷情备采》
D. 《海国图志》
