问题 选择题

材料的应用和发展与人类文明的进步紧密相关。下列材料属于有机合成材料的是         (    )

A.陶瓷

B.青铜

C.聚乙烯

D.不锈钢

答案

答案:C

考点:

专题:结合课本知识的信息.

分析:有机合成材料是指用有机高分子化合物制成的材料,可根据定义进行解答.

解答:解:A、陶瓷是一种无机材料.

B、青铜也是无机材料,属于合金.

C、由聚乙烯制成的材料是一种塑料,我们日常生活中食品包装袋等,属有机合成材料.

D、玻璃钢是一种有多种成份组成的复合材料.

故选C

点评:注意记忆常见的合成材料,主要有三大类:塑料、合成纤维、合成橡胶.要和天然纤维、橡胶区分.

完形填空

第二节(共5小题;每小题2.5分,满分12.5分)

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

People know the dangers of fires. It’s good for a family to learn how to prepare for a fire. Here are some suggestions.

Put a smoke alarm in the house. The alarm makes a loud sound.   71    

Make escape plans. They should know all the ways out of the house. If there is a fire, everyone follows the plan to get out.   72  

Practise for a fire. They do fire practice because they teach children about fire safety.Everyone in the family should know the following fire rules:

Don't open a hot door! The fire can grow more quickly if you open the door. 73   Smoke can be more dangerous than fire. The best air is near the floor because smoke rises.

What will you do if your hair or clothes start to burn? First, don’t run! The fire burns faster because of more air. Drop! Fall to the floor. Then roll!    74    Put a blanket around you to keep air away from the fire that may still be on you.

There are many possible causes for fires.    75    If there is a fire, don’t forget to call 119 for help.

A.Turning over and over will make the fire go out.

B.Smoke from a fire causes the alarm to go off.

C.The cleanest air is found at the top.

D.Stay close to the floor!E. A wise family is ready all the time.

F. Make sure all the windows can be opened easily.

G. Do not go back to the house for any reason.

问答题 简答题