问题 选择题

下列物质中不能在氧气里燃烧的是

A.氮气

B.氢气

C.硫磺

D.铁

答案

答案:A

考点:

专题:结合课本知识的信息.

分析:氮气不能在氧气里燃烧;氢气在氧气中燃烧能生成水,硫磺在氧气中燃烧能生成二氧化硫,铁在氧气中燃烧能生成四氧化三铁.

解答:解:氢气、硫磺、铁等物质能够在氧气中燃烧,氮气不能在氧气中燃烧.

故选A.

点评:解答本题要充分理解氮气、氢气、硫磺、铁等物质的性质,根据所学知识判断物质能否在氧气中燃烧.

阅读理解

阅读理解。

     When people want to know about the weather, they usually go to their radios, TVs, newspapers, or to the

Internet. However, you can also find many weather signs among wildlife, because of their highly developed

senses. Drops in air pressure (压力) produce an effect on small animals in many ways. Mice and deer are

good weather indicators. People who spend a lot of time outdoors have observed that, before a storm, field

mice come out of their holes and run around. Deer leave high ground and come down from the mountains.

     Birds are especially good weather indicators because they also show the effect of a pressure drop in many

ways. For example, some birds become irritable (急躁的) and quarrelsome and will fight over a piece of bread.

Other birds chirp (叽叽喳喳) and sing just before a storm. It seems they know they won't get another chance

for an hour or two. Birds also seek safe places before a storm. You will sometimes see birds settling in trees

or gathering together on a wire close to a building. Pre-storm low pressure makes the air so thin that birds

have difficulty flying.

     It is unusual to see many birds flying overhead in the summertime, rather than during the periods in the

spring or autumn. Watch for other weather signs if you see this. If they fly in the wrong direction, they may

be flying ahead of a storm.

     By paying closer attention to some important signs in nature, we can become better prepared for any kind

of weather.

1. The word "indicators" in paragraph 1 probably means _____.

A. maps

B. services

C. signs

D. stations

2. There will be a storm if birds _____. 

A. make more noise than usual

B. fly in different directions

C. come down from tall trees

D. share a piece of bread

3. How can birds sense the coming of a storm? 

A. By feeling a drop in air temperature.

B. By noticing the change of wind directions.

C. By feeling a drop in air pressure.

D. By noticing the movements of other animals.

4. The best title for the text would be _____. 

A. Signs of a Storm

B. Drops in Air Pressure

C. Animals' Sharp Senses

D. Nature's Weather Signs

阅读理解

阅读理解。

     There're five people at our table, including myself. I've already learnt a great deal about them in the

short time we've been at sea, although we rarely meet except at meal times.

     First of all, there's Dr Stone. He's a man of about sixty five, with gray hair and a friendly face. He

gave up his work a short while ago and is now traveling round the world before he retires to some quiet

country village. As a young man, he served for many years as a doctor in the Army and visited many

countries. He's told us a lot about the city to which we are going.

     Then there's "Grandmother". I call her that because her name escapes me. In spite of being a

grandmother, she looks rather young, not more than fifty, She's on her way to visit a daughter who went

to Australia some years ago. Naturally she is very excited at the thought of seeing her again, and her

three grandchildren, whom she has never seen.

     Then there's a man I don't care for very much, an engineer by the name of Barlow. He has been on

leave in England and is now returning to his work in Singapore.

     The other person who sits at our table is Mrs. Hunt. I've found out hardly anything about her. She's

extremely quiet and rarely talks, except to consult (咨询) the doctor about children's various illness.

She's on her way to join her husband in India.

1. What can we know about Mr. Stone?

A. He is a doctor in the Army now.

B. He is going to give up his work.

C. He knows a lot about the city the author is going to.

D. He has been retired for many years.

2. The writer calls the second person "Grandmother" because_______.

A. she looks old

B. She has three daughters

C. he respects her

D. he can't think of her name

3. Which of the following is TRUE?

A. Dr Stone lives in a quiet village now.

B. "Grandmother" is an Australian.

C. Barlow works in Singapore

D. Mrs Hunt is a woman of many words.