问题
填空题
小明手中有两块不同的透镜，他想用透镜对太阳光的作用来辨别那块是凸透镜．具体的做法如图所示：取一个透镜正对着太阳光，并在透镜正下方放一张白纸，不断调整白纸的位置，直到白纸上出现一个有小又亮的光斑，测的这个光斑到到透镜中心的距离为5cm，一段时间过后白纸燃烧，由此可知该透镜 ____（填“是”或“不是”）凸透镜，其焦距为____cm．
答案
是；5
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小明手中有两块不同的透镜，他想用透镜对太阳光的作用来辨别那块是凸透镜．具体的做法如图所示：取一个透镜正对着太阳光，并在透镜正下方放一张白纸，不断调整白纸的位置，直到白纸上出现一个有小又亮的光斑，测的这个光斑到到透镜中心的距离为5cm，一段时间过后白纸燃烧，由此可知该透镜 ____（填“是”或“不是”）凸透镜，其焦距为____cm．
是；5
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| A man hired a taxi outside the airfield. The cab had a woolen carpet with 1 lace edges. On the glass partition that 2 the driver's seat was a copy of a famous painting. Its windows were all clean. The customer was very much 3 and said to the driver,"I've never seen a nicer 4 . ""Thank you for your praise. "the driver answered 5 . "The car isn't mine,"said the driver. "It belongs to the company. I used to be a 6 of cabs. When they returned,all of them were as 7 as garbage cans with cigarette butts and rubbish 8 here and there. On the seats and door-handles could be found something 9 like peanut sauce or, chewing gum. Why so? I thought if the car itself were very clean the passengers would most 10 be considerate and refrain from littering. " "So when I got a 11 to be a taxi-driver,I began 12 my idea into practice-to tidy and 13 the car. Now before a new passenger gets on my car,I'd make a cheek and be sure it is in goo  d order. Whenmy car 14 after a day's work,it always remains 15 . " When doing a thing,one makes efforts and wants to see the result. To change others,one has to make twice the 16 but get half the result. To change oneself is the other way round-more fruit with less effort. One had better ask oneself why one makes 17 on others much more than on oneself. 18 you take enough care to do as best you can for other people's sake,your efforts will yield results,If you 19 the inner world of your own,examine yourself and wipe out the dust and dirt,instead of fixing your eyes on other people,you will find a cheerful 20 for yourself and create a pleasant environment for others. | ||||
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