[单项选择]

If the population of the earth goes on increasing at its current rate, there will eventually not be enough resources left to sustain life in the planet. By the middle of the 21 st century, if present trends go on, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on the earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Cart Sagan.
　　Sagan believes that before the earth’s resources are completely exhausted it will be possible to change that atmosphere of Venus and so create a new world almost as large as the earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
　　Sag
A. we fire the rockets containing algae into the atmosphere of Venus
B. we change Venus temperature
C. we make it possible to rain on Venus
D. we change the atmosphere on Venus

[单项选择]

If the population of the earth goes on increasing at its current rate, there will eventually not be enough resources left to sustain life in the planet. By the middle of the 21 st century, if present trends go on, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on the earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Cart Sagan.
　　Sagan believes that before the earth’s resources are completely exhausted it will be possible to change that atmosphere of Venus and so create a new world almost as large as the earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
　　Sag
A. Lack of oil.
B. Lack of food.
C. Lack of space.
D. Lack of resources.

[单项选择]If the population of the Earth goes on increasing at its present rate, by the middle of the 21^stcentury we______all the oil that drives our cars.
A. will use up
B. will have used up
C. have used up
D. will have been using up

[单项选择]

　　If the population of the earth goes on increasing at its current rate, there will eventually not be enough resources left to sustain life in the planet. By the middle of the 21 st century, if present trends go on, we will have used up all the oil that drives our cars, for example. Even if scientists develop new ways of feeding the human race, the crowded conditions on the earth will make it necessary for us to look for open space somewhere else. But none of the other planets in our solar system are capable of supporting life at present. One possible solution to the problem, however, has recently been suggested by an American scientist, Professor Cart Sagan.
　　Sagan believes that before the earth’s resources are completely exhausted it will be possible to change that atmosphere of Venus and so create a new world almost as large as the earth itself. The difficulty is that Venus is much hotter than the earth and there is only a tiny amount of water there.
　　S
A. Lack of oil.
B. Lack of food.
C. Lack of space.
D. Lack of resources.

[单项选择]If the world population is increasing continuously，food supplies will not be ______ to feed them.
A. sufficient
B. efficient
C. equal
D. effective

[单项选择]The population will be increasing very fast unless they （） with new methods to deal with it.
A. come to
B. come away
C. come over
D. come up

[单项选择]An increasing proportion of our population, unable to live without advanced medical________, will become more dependent on the development of modern technology.
A. interference
B. interruption
C. intervention
D. interaction