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

On August 27, 1783, the people of the village of Gomesse, in France, looked up into the sky and saw a strange and terrible animal. It was huge and round, flying down from the sky. It landed in the field just outside the village. It was clear to the people of Gomesse that they had to defend themselves. The animal was clearly some kind of terrible “spirit”. They were afraid of the spirit but they were also very brave. They rushed out into the field and fought the animal with knives and sticks and farming tools. The “spirit” made terrible noises, like an animal that can breathe only with great difficulty.

But that was not the worst thing. When the villagers cut into the spirit's skin, it gave off a horrible smell, and even after the villagers had cut the thing open, it still moved. Finally the villagers tied it to a horse. The horse ran through the fields and the “Spirit” was torn to pieces. What was the terrible spirit? The answer is that it was one of the first “hot air balloons气球”. Its skin was made of silk and a kind of rubber. The terrible smell was the hot air inside the balloon. When the air got out through the cuts in the skin, it also caused the horrible noises.

1. The terrible noises were made because        .

A. the spirit could hardly breathe

B. the spirit wanted to frighten the villagers

C. the spirit was afraid of the villagers

D. hot air got out through the skin

2. The terrible smell was        .

A. the smell of silk and rubber

B. the hot air inside the balloon

C. the smell of burnt house

D. the smell of burnt crops

3. The spirit didn't stop moving until        .

A. the hot air in it ran out completely

B. the villagers cut into its skin

C. the villagers cut it open

D. it gave off a horrible smell

4. The villagers tied the spirit to a horse        .

A. shortly after they caught sight of the spirit

B. because it didn't stop moving though it was cut open

C. after it was torn to pieces

D. because the villagers wanted to take it away

单项选择题