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问题 单项选择题

下列不是发球技术错误动作的是（）。

A、挥拍路线不正确

B、握拍不正确

C、掌握不好球下落与挥拍之间的时空关系

答案

参考答案：B

阅读理解
阅读理解。根据短文内容，完成表格。（每空填l 至3个词） 
      China has decided to stop the use of free plastic bags. Supermarkets, shops and outlets
(经销店) in China can't offer plastic bags any more.
      Every year, people use too many plastic bags. They throw them here and there after they
have used them. The government has done its best to deal with them but failed. While we offer
quick service (服务) to customers, the plastic bags pollute water, earth and air, and they waste
the oil. The government asks people to go back to carry cloth bags and use baskets when they
go to buy something. The cloth bags and the baskets can be used again and again.
     Many months have passed. The environment has been improved a lot.
Action Make a decision to stop the use of 1.______.
2.______ Supermarkets, shops and outlets 
AdvantageOffer 3._______ service to customers
Disadvantage Pollute water, earth and air and waste 4._______
What should we do Go back to carry cloth bags and use 5._______
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填空题

（10分）X、Y、Z为不同短周期非金属元素的气态单质。在一定条件下能发生如下反应：

Y+X→甲（g），Y+Z→乙（g）。甲、乙可化合生成离子化合物，甲的相对分子质量小于乙。

（1）X的结构式是                    。

（2）磷在Z气体中燃烧可生成液态丙分子，也可生成固态丁分子。已知丙分子中各原子最外层均是8电子结构，丙的电子式是                 。磷单质和Z单质反应生成1mol丙时，反应过程与能量变化如图I所示，该反应的热化学方程式是                 。

（3）某同学拟用图II所示证明氧化性Z>I2，已知高锰酸钾与乙的浓溶液反应生成Z，则a是        的水溶液。若仅将a换为甲的浓溶液，实验时会产生大量白烟并有气体单质生成，该反应的化学方程式是                               

（4）向一定浓度的BaC12溶液中通入SO2气体，未见沉淀生成，若在通入SO2气体的同时加入由甲和乙中的一种或几种元素组成的某纯净物，即可生成白色沉淀，该纯净物可能是           、           。
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