问题 问答题

氧气是化学性质比较活泼的气体,可以与许多物质发生反应.氧气的这一特性,使氧气在生产和生活中有着广泛的应用;也正是由于氧气的这一性质,人们为了生产和生活的需要,在某些情况下,要使物质与氧气隔绝.请你从以上两个方面各举一例予以说明.应用氧气:______;隔绝氧气:______.

答案

(1)①氧气的物理性质:密度比空气的大;②化学性质:助燃性,氧化性,供给呼吸.(2)性质决定用途.(3)金属表面涂漆,涂油,为了防止金属生锈. (4)锅中油起火,盖上锅盖,隔绝氧气来灭火.

故答为:呼吸;燃烧     灭火;刷漆防锈

阅读理解

When you are in England, you must be very careful in the streets because the traffic drives on the left.

Before you cross a street, you must look to the right first and then left. If the traffic lights are red, the traffic must stop. Then the people on foot can cross the road.

If the traffic lights are green, the traffic can go. People on foot mustn’t cross.

In the morning and in the evening when people go to or come from work, the streets are very busy. Traffic is most dangerous then.

When you go by bus in England, you have to be careful, too. Always remember the traffic moves on the left. So you must be careful. Have a look first or you will go the wrong way.

In many English cities, there are big buses with two floors. You can sit on the second floor. From there you can see the city very clearly. It’s very interesting.

小题1:When you are in England, you must always remember that_________.

A.there are many cars and buses on the road.

B.the traffic drives on the left.

C.there are not any traffic lights.

D.the traffic drives on the right.小题2:In China, before you cross a street, you must look to _______ first and then ________.

A.the left; the right

B.the right; the left

C.the front; the back

D.the back; the front小题3: You must be careful when you go by bus because __________.

A.there are too many buses there

B.the traffic lights are different from ours

C.crossing the street is dangerous

D.you may go the wrong way小题4:In England, it is very interesting to _________.

A.cross the streets

B.look at the traffic lights

C.sit on the second floor of a big bus and see the beautiful city

D.look at the busy streets in the morning小题5: Which is the best title(题目)?

A.Buses in England  

B.Traffic in England

C.Travelling in England

D.Traffic lights in England

单项选择题