问题 单项选择题

乙炔气体的性质不包括()。

A、乙炔与空气混合点燃有可能会爆炸

B、乙炔是一种可燃气体

C、乙炔燃烧产生大量的热

D、乙炔与空气混合一定会爆炸

答案

参考答案:D

阅读理解

Many people in the world live in big cities, which are often dirty and difficult places to live. So, some cities will get bigger. They will also get higher, and lower, because people will begin to live under the ground as well as in tall buildings. Scientists also say that men can begin to live in cities under the sea, when there is not enough space on the land. Of course, these new cities will be very expensive, and difficult to build, but they are not impossible. Already, some countries are building places to live under the ground so their people can go there if there is a new war. There are underground cities in Switzerland(瑞士)and China, built by the government(政府)to help some of the people live during a great war. 

But will people change if they live under the ground for a long time?For example some fish go blind if they live in the dark sea for a long time. People will not go blind, because there will be light underground, but they may change in some way. Scientists say that people who live in cities today are losing their senses of smell, touch and taste. They can’t smell the dirty air, they can’t taste the chemicals(化学制剂)in their food. These senses are not as strong as before, when people lived in the country and grew their own food. The city has changed that. What will the underground city change in everyone?

小题1:People will live under the ground because _________. 

A.it’s neither hot nor cold there

B.they’ll be afraid of the war

C.there’ll be less space on the ground

D.they’ll make their life comfortable小题2:Some countries try to build some places under the ground so that people will be able to live there _____.

A.when summer comes

B.when a war breaks out

C.because they think it’ll be safer for them

D.when they’re fed up with the life on the land小题3:_________, so people who will live there won’t go blind. 

A.There’ll be enough light under the ground

B.It’ll be easy to go upstairs

C.Glasses will be sold under the ground

D.Medicine will be supplied for free小题4:People will lose some senses under the ground because _______.

A.the world are polluted

B.it’s dark there

C.the air is dirty and there are a lot of chemicals in their food

D.they can’t grow their own food in the sun

单项选择题