搜题请搜索小程序“爱下问搜题”
问题 选择题

全球性环境污染问题指的是（　　）

A．水土流失、沙尘暴、水体富营养化

B．砍伐森林、围湖造田、水华

C．酸雨、温室效应、臭氧层破坏

D．过多使用农药、使用含磷洗衣粉

答案

全球性大气污染最主要的问题就是酸雨、温室效应和臭氧层破坏．
    酸雨：PH＜5.6的雨水，是由于燃烧煤、石油、然气时产生过多的二氧化硫和氮氧化物等有害气体，在到大气中与雨水结合，导致酸雨的产生．酸雨的危害：使土壤的养发生变化，从而不能被植物吸收，使河流和湖泊酸化，影响鱼虾繁殖甚至死亡，危害植物的芽和叶，严重时使成片植物死亡，对各种生物和各种建筑物都造成了巨大的伤害．被称为“空中死神”．
    温室效应是指由于全球二氧化碳等气体的排放量不断增加，导致地球平均温度不断上升的现象，导致冰川融化、海平面上升等一系列的问题．
    臭氧层是指大气层的平流层中臭氧浓度相对较高的部分，其主要作用是吸收短波紫外线．大多数科学家认为，人类过多地使用氯氟烃类化学物质（用CFCs表示）是破坏臭氧层的主要原因．控制和停止使用氟利昂，以及减少含氮废气的排放等，是防止臭氧层破坏的关键．
故选：C．

选择题

We can’t accurately    what will happen next.   

A．debate

B．speak

C．analyse

D．predict
查看答案
阅读理解
阅读理解。
     A new generation addiction is quickly spreading all over the
world. Weboholism, a twentieth century disease, affects people from
different ages. They surf the net, use e-mail and speak in chat rooms.
They spend many hours on the computer, and it becomes a compulsive
habit. They cannot stop, and it affects their lives.
     Ten years ago, no one thought that using computers could
become compulsive behavior that could affect the social and 		  
physical life of computer users. This obsessional behavior has affected teenagers and college students. They
are likely to log on computers and spend long hours at different websites.
     They become addicted to computers and gradually their social and school life is affected by this situation.
They spend all free time surfing and don't concentrate on homework, so this addiction influences their grades
and success at school. Because they can find everything on the websites, they hang out there. Moreover, this
addiction to websites influences their social life.
     They spend more time in front of computers than with their friends. The relation with their friends changes.
The virtual life becomes more important than their real life. They have a new language that they speak in the
chat rooms and it causes cultural changes in society.
     Because of the change in their behavior, they begin to isolate themselves from the society and live with their
virtual friends. They share their emotions and feelings with friends who they have never met in their life.
Although they feel confident on the computer, they are not confident with real live friends they have known all
their life. It is a problem for the future. This addictive behavior is beginning to affect all the world.
1. The author's attitude towards weboholism is that of being _____.
A. optimistic
B. positive
C. oppositive
D. acceptable
2. The main idea of the passage is about _____.
A. the cause of weboholism
B. the advantage of weboholism
C. the popularity of weboholism
D. the influence of weboholism
3. The underlined word "obsessional" in the second paragraph most probably means "_____".
A. attractive
B. professional
C. addictive
D. potential
4. We can infer from the passage that _____.
A. weboholism has the greatest effect on teenagers
B. virtual life is more vivid and attractive anyway
C. people are addicted to games on the Internet
D. students can hardly balance real and virtual life
查看答案