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问题 选择题

标准状况下，有一真空储气瓶，装满氧气后重508克，装满二氧化碳后重511克，问该瓶的容积为（　　）

A．5.6 L

B．11.2 L

C．22.4 L

D．2.8L

答案

标准状况下，真空储气瓶的体积不变，则装满氧气与二氧化碳的物质的量相同，

设瓶的质量为x，则

508g-x
32g/mol
=
511g-x
44g/mol
，

解得x=500g，

则n（O2）=

8g
32g/mol
=0.25mol，

所以该瓶的容积为0.25mol×22.4L/mol=5.6L，

故选A．

判断题

在同一个国家范围内的经济金融活动不存在国家风险。( )
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完形填空

There is good news for the children in the      . We may still remember the girl       big eyes. Her big eyes       us her dream: I wish to go to school. In China, there are still       girls and boys like her. They want to go to school,        their families are too poor. If the family has two or three children, it is harder for them to       the education for all the children. So the parents often ask girls       at home, and boys to go to school.

Now they       worry about the money. From 2006 on, children could go to school for free in some poor places. They don’t have to pay for books and other things. Some of them can even get money from the government to make their life       . Soon all the children in the countryside can go to school for free. All families are very happy with the news. It is       great. China that has changed for the better.

小题1:A. cities             B. countryside         C. farm

小题2:A. with              B. on                  C. in

小题3:A. says              B. tells                  C. talks

小题4:A. a lot             B. much                C. a lot of        

小题5:A. but           B. and                C. or

小题6:A. take              B. afford                 C. spend

小题7:A. stay          B. staying            C. to stay 

小题8:A. mustn’t          B. needn’t            C. can’t

小题9:A. better         B. worse                  C. longer      

小题10:A. really       B. never                   C. hardly  
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