题目

托盘天平是科学实验中常用的仪器。下列有关其使用的说法中不正确的是A. 称量物体前首先应估计被测物体的质量，以免超过量程B. 称量时，向右移动游码，相当于向右盘加砝码C. 不管桌面是否水平，只要调平横梁就可以称量D. 不能把化学药品直接放在托盘上称量 答案：【答案】C【解析】天平是等臂杠杆，称量时根据杠杆平衡的条件可知，左边重力等于右边重力，即可得出称量结果，若桌面不平，两边力臂仍不相等，所以无法使用.故选C. 完形填空。      During a recent vacation I visited Dusseldorf, a city in the dormer West Germany. The nine-day trip lefta deep impression on me. I arrived at Dusseldorf airport at six. It was already dark outside. The first thing I needed to do was to find a place to   1  . I decided to telephone the youth hotel. But to use the   2   I neededsome coins. I asked a lady for help. To my   3  , she   4   me five coins to use! But all the phones in the   5   needed phone cards. And phone cards could only be   6   at post office during the daytime. I was afraid I wouldn't be able to call the   7  . An old gentleman helped me. He couldn't speak English but   8   that I neededto make a phone call. He showed me where the   9   was and inserted (插入) his phone card. I called the youthhotel and found a place to stay that night. The kindness of the German people made me feel  10  and it seemedthat I was not far from  11 . And my first day in Germany wasn't as  12  as I expected previously.      Whenever I went, I asked people for  13 . What surprised me most was that almost every young Germancould tell me the way in  14  English. Older Germans couldn't speak English so well,  15 , they would try tohelp me whenever they could. One middle-aged man I asked for directions even  16  me to the place I was looking for. My experience in Germany completely changed my  17  of Germans. Before, I thought they were unfriendly to foreigners. In the World War II in the 1940s, Germans were always  18 . But things have  19  since then. And Germans today couldn't be more  20 , in my opinion. (     )1.A.study (     )2.A.hotel (     )3.A.surprise (     )4.A.covered (     )5.A.college (     )6.A.bought (     )7.A.police (     )8.A.explained (     )9.A.phone (     )10.A.amased (     )11.A.Germany (     )12.A.brilliant (     )13.A.directions (     )14.A.immediate (     )15.A.as a result(     )16.A.waved (     )17.A.enthusiam (     )18.A.amusing (     )19.A.completed (     )20.A.good-looking B.stay B.taxiB.disappointment   B.shared B.airport B.found B.websiteB.admitted B.coins B.shyB.homeB.interesting B.instructions B.fluent B.however B.movedB.behaviour B.serious B.changed B.energetic C.work C.phone C.joy C.organised C.activities C.used C.hotel C.appreciated      C.card C.nervous C.the hotel C.terrible C.discipline C.incorrect C.so that C.drove C.impressionC.impatient C.improved C.stupid D.visit D.money D.delight D.gave D.vacasion D.kept D.headmaster D.understood D.post-office D.relaxed D.province D.formal D.topicsD.scientific D.in other words         D.followedD.interest D.cruel D.avoided D.friendly