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问题 单项选择题

在滤清器上装有（）是为了保证进入喷油泵油室内的柴油油压稳定。

A.油管

B.限压阀

C.单向阀

D.溢流阀

答案

参考答案：B

选择题

用NA表示阿伏德罗常数，下列叙述正确的是(    )

A．标准状况下，22.4LH2O含有的分子数为NA

B．2.7g金属铝无论与强碱还是强酸作用时失去电子数目均为0.3NA

C．常温常压下，1.06g Na2CO3固体含有的Na+离子数为0.01 NA

D．物质的量浓度为0.5 mol/L的MgCl2溶液中，含有Cl-个数为NA
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填空题
用方框内所给单词的适当形式填空。

photo, lie, wash, child, she, listen, have
1. She often __________ a good time on the school trip.
2. Look! The dog __________ on the ground.
3. She has no book. Please give it to __________.
4. June 1st is __________ Day.
5. The girls are __________ the clothes now.
6. They are __________ to the radio now.
7. Do you often take any __________?
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