问题 选择题

利用托里拆利实验测大气压时,可以确认管内进入了少量空气的现象是(  )

A.管内水银面的高度略小于760毫米

B.使管倾斜时,管内水银柱长度增加

C.无论怎样使管倾斜,水银都不能充满全管

D.将管在水银槽内轻轻上提,管内水银柱高度不变

答案

A、天气、环境、海拔等因素也可能使水银柱高度略小于760mm,所以不能确定就一定是混入了空气;

B、使管倾斜,管内的水银柱高度还须保持原来的垂直高度,所以长自然会增加;

C、如果把管倾斜到垂直高度明显低于大气压能支持的水银柱高了水银还不能充满全管,那只能说明一个问题,那就是那里边是有东西的,那个东西当然就是偷跑进去的空气啦;

D、管在水银槽内轻轻上提,只要管口不离开水银面,管内水银面也会随之略微下降,而高度不变.

故选C.

阅读理解

When tea and coffee were first introduced to Europe in the 18th century, people had different ideas about their use.Some said that tea and coffee were harmful to humans and they could cause (引起)people to die.

In Sweden(瑞典), King Gustaf Ⅲ decided to find out whether or not this was true.It happened that there were two brothers in prison at that time.They were twins and were almost alike in every way.They had both been sentenced to death (判处死刑).The King decided to let them live if one of the men agreed to drink several cups of tea each day and the other several cups of coffee.

Both brothers lived many years without problems of any kind.At last,the brother who had drunk tea every day died at the age of 83,the other died a few years later.

Because of the experiment(实验), tea and coffee got accepted (接受) and became popular as drink in Sweden, and it is one of the many countries of the world where much tea and coffee is drunk today.

小题1:Tea and coffee were first introducd to Europe in_______.

A.the eighteenth century

B.the eighteen century

C.eighteenth centuries

D.eighteen centuries小题2:What does the word harmful mean in Chinese?---It means________.

A.有趣的

B.苦涩无味的

C.有害的

D.可口的小题3: The brother who had drunk tea every day lived______.

A.until he was over 83

B.until he was 83

C.until the other had been dead for several years

D.until he had drunk tea for a few years小题4:. Today the Swedish drink_________.

A.much more coffee than tea

B.much tea and coffee

C.little tea and coffee

D.much tea but little coffee

单项选择题