车速里程表主要由()、铝碗、罩壳、盘形弹簧、刻度盘和指针六部分组成。 A.永久磁铁

题型:单项选择题

问题:

车速里程表主要由()、铝碗、罩壳、盘形弹簧、刻度盘和指针六部分组成。

A.永久磁铁

B.电阻

C.转子

D.黄铜片

考点:机动车维修技术汽车检测与维修汽车检测与维修题库
题型:单项选择题

阅读下列短文,从文后所给A、B、C、D四个选项中选出一个最佳答案。
John Thomas was an 18-year-old student, but he had been a famous champion (冠军).  Everybody at Boston University liked this tall, quiet boy. Once he was hurt, everybody at Boston University was  36  . People all over the country  37  about John Thomas and often asked, "Will he ever jump again ?"
John' s mother went to the hospital to see her son. She looked at his 38 leg. Then she looked into his  39  .She knew what her son would  40 . "You're going to jump again, John, I know it," she said. "  41  will be all right. "
If John hoped to jump again, he would have a  42  to do. He began at once. Even in his hospital bed John started to exercise. He used a wheel(轮子) and other metal things. Soon his  43  looked like a machine shop!
It was May when John  44  the hospital. "Is it all right if I go camping( 宿营) this summer?" he asked the doctors.
" Yes," the doctors said.  " But take it easy on that foot. "
John took only  45 walks at first. He was taking it easy on his foot. But not on anything else. He went swimming and did other kinds of exercises. He exercised  46  his body cried for a rest. Some days later, he exercised a little  47  . In late summer John went back to  48  . He asked if he could practise with the football team. Football wasn't his favorite, but he had to get that leg  49  again! He worked hard. "No one pushed him as hard as he pushed himself," said one of his friends. "To  50 a champion fighting back is a wonderful thing to watch. ":
小题1:
A.sorryB.afraidC.aloneD.tired
小题2:
A.thoughtB.talkedC.heardD.moved
小题3:
A.brokenB.lostC.missingD.dead
小题4:
A.faceB.footC.eyesD.leg
小题5:
A.makeB.useC.agreeD.do
小题6:
A.NothingB.AnythingC.SomethingD.Everything
小题7:
A.littleB.lotC.fewD.bit
小题8:
A.chairB.classroomC.homeD.bed
小题9:
A.reachedB.calledC.leftD.found
小题10:
A.shortB.longC.quickD.fast
小题11:
A.afterB.ifC.untilD.when
小题12:
A.laterB.betterC.moreD.less
小题13:
A.schoolB.hospitalC.shopD.church
小题14:
A.thickB.strongC.straightD.hard
小题15:
A.lookB.hearC.knowD.see
题型:单项选择题
已知一系列的抛物线Cn的方程为y=anx2(n∈N*,an>1),过点An(n,ann2)作该抛物线Cn的切线ln与y轴交于点 Bn,Fn是 Cn的焦点,△AnBnFn的面积为n3
(1)求数列{an}的通项公式;
(2)求证:1+
3
2
≤an<2;
(3)设bn=2an-an2,求证:当n≥1时,b1+
2
b2+
3
b3+…+
n
bn
3
4
题型:单项选择题

我国历史悠久,文化灿烂,文物众多。由于历史的原因,造成众多文物流失。2000年5月,在香港拍卖会上,保利集团花费3000多万港币购回火烧圆明园时流失的国宝——铜铸的牛首、猴首和虎首。普通铜器放置时间较长,容易出现铜绿,其主要成分是Cu2(OH)2CO3。这三件1760年铜铸的国宝在240年后看上去依然熠熠生辉,不生锈,下列对其原因的分析,最可能的是(   )

A.它们的表面都镀上了一层耐腐蚀的黄金

B.环境污染日趋严重,它们表面的铜绿被酸雨溶解洗去

C.铜的金属活动性比氢小,因此不易被氧化

D.铸造这些国宝用的铜不是纯铜,是铜的合金,成分不同,性质不同造成的

题型:单项选择题

普通玻璃是______(填“混合物、纯净物”).玻璃可在一定温度范围内软化,没有固定的______.三大合成材料是指塑料、______和______.塑料的主要成分是______,可分为______性塑料和______性塑料.

题型:单项选择题

风湿性心脏瓣膜病二尖瓣狭窄的特征性体征是()。

A.心尖区舒张中晚期隆隆样杂音,递增型

B.第一心音亢进

C.肺动脉瓣区舒张早期吹风样杂音

D.Graham-Steell杂音

E.二尖瓣开放拍击音

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