临床前期长的某些患者被筛查到的机会要比，临床前期短的病人大，而前者的生存期要比后者长

冷战正式开始的标志是[ ]

A．德国突袭波兰

B．丘吉尔富尔顿演说

C．“杜鲁门主义”出台

D．萨拉热窝事件

The earth is our home；we must take Care of it. This means keeping the land，air and water   clean.

Pollution is a dirty word. To pollute means to make things unfit(不合适的)or unclean to use. Pollution comes in many ways. We see it，smell it，taste it and drink it. Pollution is beginning to threaten(威胁)our health，or happiness and our life.

Man. has been polluting the earth from the time he first made fire，washed his clothes in the river and threw his waste on the ground. When land was used up or water became dirty. Men moved to another place. At first the problem was not so serious because there was plenty of clean air，land and water. There weren’t so many people then and their wants(需求)were fewer. All the dirty things could be absorbed(吸收)by nature and soon. covered over(恢复)， But this is no longer true. The increase of population(人口增长)and the development of industry have changed that. Man is slowly polluting. his environment.

Through the use of poison(农药)，mall has polluted land! killing the animal. By putting dirty water and chemicals into rivers and lakes we have polluted our drinking water，killing the fish.

Our increasing population is part of the problem. More people more waste.

Where is this all to end? Are we turning the world into a big rubbish dump，or is there any hope that we can get rid of(摆脱)the pollution ?Luckily，millions of people have been warned of the danger of pollution. Large numbers of people are now working hard to bring pollution under

小题1:Which sentence is WRONG?

A．We live on the earth，so we should look after it.

B．To pollute means to make air ，water and land unfit for use.

C．All the waste produced by modem industry can be absorbed.

D．Man is now fighting against different kinds of pollution.小题2:In this passage the word "chemicals" means

A．化学

B．化学物质

C．化学的

D．医学的小题3: From the sentences "More people more waste"，we know that _______.

A．because of the increase of population and the development of industry，more and more waste is produced

B．we need more people，not more waste

C．there isn’t any hope that we can get rid of the pollution

D．more people have been warned of the danger of more waste.小题4:From the passage we can know that now man_______.

A．doesn’t know how to control pollution

B．still doesn’t realize how serious pollution is

C．is doing something to control pollution

D．begins to understand the pollution

早春播种后，用塑料薄膜覆盖地面，会促进提早出苗的原因是（　　）

A．雨水没有浸泡种子

B．清洁的地面容易出苗

C．塑料本身有促进物质

D．提高表层土壤的温度

IPV6功能改进主要体现在（），引入即插即用功能和具有QOS等几个方面

A.128bit的地址空间

B.网络地址分层结构

C.高效的路由寻址效率

D.安全功能的增强

晶体二级管能使（）。

A、交流电变为直流电

B、直流电变为交流电

C、两者都行