Since the earliest times, trees have always been very useful and important to man who made use of them in many ways．Even today trees continue to serve man so many ways．
Trees provide man with fruits and buildings in the form of wood．Without trees it would be impossible to build houses, boats and even bridges．Furniture(家具)such as tables, chairs and beds is made of wood．
In the tropics(热带地区)where it is very hot all through the year, trees protect man from the terrible heat．They are also useful in preventing good and rich top soil from being washed away during heavy rains which are so common in the tropics．
If there were no trees or vegetation(植被)of some kinds to hold back the soil with their roots soil, heavy rains would wash away the rich top soil that is so important and necessary to crops．The result is that the land becomes a desert．
There are so many desert areas in the world．A long time ago these desert areas must have been very rich soil areas, but since the people in the past hadn't enough knowledge about science of nature, they cut down all the trees in the areas where they lived and never planted new ones．By and by, the rich top soil was blown away and washed away by strong winds and heavy rains．In the end the land was turned into useless deserts where nothing could grow．
(1)
According to the passage ________．
[ ]
A．
people in the past did know how to make good use of trees
B．
trees were more useful in the past than they are now
C．
trees are not as useful now as they used to be
D．
trees has always been very useful to man
(2)
The phrase“top soil”means ________．
[ ]
A．
useless soil which is of no use for crops
B．
soil on the top of the earth which is good for crops
C．
a kind of soil which is found deep under trees
D．
dry soil in desert areas which is bad for crops
(3)
According to the passage, some desert areas were once ________．
[ ]
A．
lands with good soil
B．
covered by ice and snow
C．
very cold
D．
very dry and useless
(4)
What would happen if there were no trees?
[ ]
A．
The land would have richer soil．
B．
Heavy rains would clean the tropics．
C．
There would be no crops at all．
D．
The rich top soil couldn't be held back．
(5)
From the passage we can see the writer wants to tell us that ________．
[ ]
A．
man can do nothing to protect the environment of nature
B．
man may do what he likes to do
C．
man must do his best to keep the earth natural and green
