题目内容：

    If the population of the earth continues to increase , there will not be enough resources (资源) left to keep life on the planet. We will use up all the oil that drives our cars sooner or later .One possible way to work out the problem, has recently been suggested by an American scientist, Professor Carl Sagan.

Sagan believes that before the earth’s resources are completely used, it will be possible to change the atmosphere of Venus(金星) and create a new world almost as large as Earth itself. The difficulty is that Venus is much hotter than the earth and there is only a little water there.

Sagan suggests that algae organisms(海藻组织) can live in very hot or cold temperatures and at the same time produce oxygen. They should be bred(养殖) in conditions similar to those on Venus. When this has been done, In a short time, the algae will break down the carbon dioxide into oxygen and carbon.

When the algae have done their work, the atmosphere will become cooler, but before man can set foot on Venus it will be necessary for the oxygen to produce rain. The surface of the planet will still be too hot for man to land on but the rain will finally fall and in a few years something like earth will be reproduced on Venus.

1.The population growth on Earth will cause the lack(缺乏) of _________.

A.food B.oil C.space D.resources

2.What is one of the difficulties for the human race to live on Venus?

A.The shortage of the algae B.The shortage of carbon

C.The much hotter weather D.The much cooler weather

3.Which of the following statements about the algae is NOT true according to the passage?

A.It can live in very hot temperatures. B.It can live in very cold temperatures.

C.It can break down the carbon dioxide. D.It can provide enough food for man.

4.This passage is mainly about __________.

A.the possibility of living on Venus B.the population of the earth

C.the American scientist Sagan D.the weather of other planets