问题 选择题

已知短周期元素甲、乙、丙、丁、戊的原子序数依次增大,它们的部分化合价如下表。下列说法正确的是

A.乙的单质中能与水剧烈反应

B.气态氢化物的稳定性:丙>甲

C.丙的氧化物能与戊的氢化物水溶液反应

D.其最高价氧化物对应的水化物的酸性:丁>戊

答案

答案:A

题目分析:由主族元素的最高正价=主族序数、最低负价=主族序数(H除外)可知,甲、乙、丙、丁、戊分别是碳、钠、硅、硫、氯;A、钠与水能剧烈反应,正确;B、非金属性:C>Si,则稳定性:CH4>SiH4,错误;C、SiO2不溶于盐酸,错误;D、非金属性:S<Cl,则酸性:H2SO4<HClO4,错误。

完形填空

Today there are policemen everywhere, but in 1700, London had no policemen at all. A few old men used to protect the city streets at night and they were not paid.

About 300 years ago, London was starting to get bigger and more and more people began to live there. The city was very dirty and many people were poor. (93). There were so many thieves who stole money in the streets that people stayed in their homes as much as possible.

In 1750, Henry Fielding started to pay a group of people to stop thieves. They were like policemen and were called "Bow Street Runners" because they worked near Bow Street.

Fifty years later, there were 120 "Bow Street Runners", but London had become very big and needed more policemen. So in 1829, the first Metropolitan (or London) Police Force was started with 3,000 officers. Most of the men worked on foot, but a few rode horses. Until 1920 all the police in London were men.

(94). Today, London police are quite well paid, especially for the few police officers who still ride horses, the pay is even better than for the others.

A.根据短文内容简要回答下列问题:

小题1:Why did people stay in their homes as much as possible about 300 years ago?

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小题2:When was the first London Police Force started with 3,000 officers?

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B. 将短文中划线的两个句子译成汉语。

小题3:________________________________________________________

小题4:________________________________________________________

小题5:请给短文拟一个适当的英文标题_______________________________

单项选择题