Life on earth depends on water, and there is no substitute for it. The current assumption is that our
basic needs for water-whether for drinking, agriculture, industry or the raising of fish will always have to
be met. Given that premise (前提) , there are two basic routes we can go:more equal access to water or
better engineering solutions.
Looking at the engineering solution first, a lot of my research concentrates on what happens to
wetlands when you build dams in river basins, particularly in Africa. The ecology of such areas is almost
entirely driven by the seasonal changes of the river-the pulse of the water. And the fact is that if you build
a dam, you generally spoil the downstream ecology. In the past, such problems have been hidden by a
lack of information. But in the near future, governments will have no excuse for their ignorance.
The engineers' ability to control water flows has created new kinds of unpredictability too. Dams in
Africa have meant fewer fish, less grazing and less flood- plain (洪泛区) agriculture-none of which were
expected. And their average economic life is assumed to be thirty years. Dams don't exist forever, but
what will replace them is not clear.
The challenge for the future is to find new means of controlling water. Although GM technology
(转基因) will allow us to breed better dry land crops, there is no market for companies to develop
crops suitable for the micro-climates of the Sahel and elsewhere in Africa. Who is going to pay for
research on locally appropriate crops in the Third World?
1. What's the main idea of this passage?
A. The challenge for the future.
B. The engineering solutions to water resource and their limitation.
C. The basic means of controlling water.
D. The challenge for developing crops.
2. Which of the following statements is NOT true for meeting our basic needs for water?
A. Water resource should be used more reasonably.
B. More dams should be built in river basins.
C. More wetlands should be protected from destruction.
D. More dry-land crops could be developed in Africa.
3. The author suggests that governments will have no excuse for their careless ignorance in the future
because .
A. the ecological destruction will be known to the public by researchers
B. the ecological destruction will no longer be a problem in the future
C. the future is an information age
D. governments will face greater challenge in the future
4. The author mentions all the problems caused by dams EXCEPT .
A. fewer fish
B. less grazing land
C. less farming land
D. less floodplain agriculture
5. The last sentence probably implies that .
A. no one will invest in developing locally appropriate crops in Africa
B. researchers have no interest in developing dry land crops
C. research on locally appropriate crops in the Third World may be profitable
D. There is less water resource in the Third World
时，物体透过凸透镜成倒立、放大、实像，所以蜡烛放在c点时成放大的实像，这是幻灯机和投影仪的原理；