[单项选择]Trees are useful to man in three very important ways: they supply him with wood and other products; they give him shade; and they help to prevent droughts and floods.
Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees. He has cut them down in large numbers, only to find that without them he has lost the best friends he had. 2000 years ago a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees, its soil became hard and poor. When the empire fell to pieces, the home country found itself faced floods and starvation.
Even if a government realizes the importance of adequate supply of trees, it is difficult for it to persuade the villager to see this. The villager wants wood to cook his food with; and he can earn money by producing charcoal or selling wood to the townsman
A. wants a plentiful supply of trees
B. wants fire wood
C. wants to get money
D. is not aware of the importance of environmental protection

[单项选择]Trees are useful to man in three very important ways: they provide him wood and other products; they give him shade; they help to prevent droughts and floods.
Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees, he has cut them down in large numbers.
Two thousand years ago, a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees; its soil became bare and poor. When the empire fell to pieces, the country found itself faced by floods and starvation.
Even where a government realizes the importance of a plentiful supply of trees, it is difficult sometimes to make the people realize this. They cut down trees but are too careless to plant and look after new ones. So, unless the government has a good system of control, or can educate the people, the forests will slowly
A. keep him from the hot sunshine
B. enable him to build warships
C. make him draw quick profit from them
D. protect him from droughts and floods

[单项选择]

Trees are useful to man in three important ways: they provide him with wood and other products; they give him shade; and they help to prevent droughts and floods.
Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important one. In eagerness to make money from trees, men have cut them down in large numbers. And besides, men are usually too careless to plant and look after new trees. So the forests slowly disappear.
This does not only mean that man will have fewer trees. The results are even more serious: for where there are trees, their roots break up soil--allowing the rain to sink in--and also bind the soil, thus preventing it from being washed away easily; but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When all the top-soil is gone, nothing remains but worthless desert.
Two thousand years ago a rich and powerful coun
A. New trees are not looked after properly.
B. Many trees have been cut down by man.
C. Man has not paid enough attention to planting trees.
D. All of the abov