问题
单项选择题 A1/A2型题
使用分析天平时，加减砝码和取放物体必须休止天平，其目的是（）。
A.加块称量速度
B.防止天平盘的摆动
C.增加天平的稳定性
D.减少玛瑙刀口的磨损
E.防止读数漂移
答案
参考答案：D
解析：原子序数为11的元素是Na，多一个质子的元素是Mg，比Na少一个电子为Mg
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使用分析天平时，加减砝码和取放物体必须休止天平，其目的是（）。
A.加块称量速度
B.防止天平盘的摆动
C.增加天平的稳定性
D.减少玛瑙刀口的磨损
E.防止读数漂移
参考答案：D
解析：原子序数为11的元素是Na，多一个质子的元素是Mg，比Na少一个电子为Mg
Choose the best answer to complete the passage. The English language is different from any 36 language. Yet English words do not 37 the same. It is always 38 . People need new words 39 new inventions and new ideas. Different words come into use or older words are used 40 a new way. English can 41 by borrowing words from other languages. The word “tomato” was borrowed from Mexico, the word “coffee” came from Turkey, and “tea” from 42 and so on. Now new space and science words 43 from other countries, too. New words are also made by adding two words 44 . The words “strawberry”, “postman” and “blackboard” are made up of two parts. Sometimes, new words are 45 forms of old words. The word “photo” was made from “photograph” by cutting off the 46 of the long word. The word “plane” was made by cutting off the 47 part of “airplane”. 48 “smog” was made by using only the first two letters of “smoke” and cutting off the front part of “fog”. And products can become new words. Our “sandwich” was named after 49 named Sandwich, and “jelly(果冻)” was a name made up by the company that 50 made this product.
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