Is necessary to complete the design before National Day?A．this B．that C．it D．he 题目和参考答案——青夏教育精英家教网—

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75.Is ____ necessary to complete the design before National Day?

A．this　　　　　

B．that　　　

C．it　　　　　　

D．he

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The “balance of nature”is not an empty phrase. Nature provides a population to occupy a suitable environment and cuts down surplus population to fit the available food supply. One means of reducing surplus population is predators; others are parasitic diseases. Also, population density produces nervous disorders and even drives animals to mass migrations(移民群),like the lemmings of Norway who plunge（冲入）into the sea.

That predatory population increase to control other animals has long been known. Many years ago, the Hudson’s Bay Company records revealed that the fox population went up and down about a year after rabbit population had gone up and down.

Sometimes a situation occurs in which the predatory population is reduced to a level below which nature can readily replace. On Valcour Island in Lake Champlain, a costly campaign resulted in the elimination（消除）of predatory animals only to have birds and small animals increase for four years afterward. Then, lacking predator control, nature resorted to disease to cut down these populations.

Jamaica had an example of nature’s persistence in providing animals for existing habits. Sugar planters, about 75 years ago, imported mongooses（狐猴）to control rats. The mongooses killed off the rats, kids, puppies, and wildlife. Eventually, food became scarce and the mongoose’s population declines.

1. The fact that the number of predators has much to do with that of other animals 　　 .

A. is not recent knowledge　　　　　　　　　　　　　　 B.has just been learned

C.hasn’t been proved yet　　　　　　　　　　　　　　　　　　　　 D.is not important now

2. When predator control fails, nature brings animal population into balance by .

A. eliminating the number of predators

B.seeking the help of disease to reduce other animals

C.increasing the number of other animals

D.replacing the number of predators immediately

3. When the mongooses killed off the rats they 　　 .

A. became problems themselves　　　　　　　　　　　　 B.ate the sugar crop

C.attacked humans　　　　　　　　　　　　　　　　　　　　 D.had nothing to eat

4. It is implied in this passage that 　　 .

A. sugar planter imported mongooses to control rats

B.man should never kill animals

C.man has complete control over nature

D.to upset the balance of nature can be troublesome

Answer each question according to the required words limit．

　　If you have ever been rock climbing, you will know that it is not a very easy sport．

　　There are three basic types．Top roping is probably the most common type and is basically climbing with a partner．Lead climbing is very similar to top roping．In both types, the climber can sit off the wall and rest on the rope．

　　Bouldering is a type of free climbing without any type of ropes or harnesses(保护带)．This is the most challenging of all types of climbing．The climber must be able to complete the task without taking a rest on the rope．

　　Believe it or not, climbing is said to be about 75％ legs and 25％ arms．To climb successfully, the climber must master a wonderful technique．One of the major rules is to always have 3 points touching the wall, whether it is both feet and one hand, or one foot and both hands, it is much easier to have your weight rest on 3 points than on 2．Another important technique to grip(抓紧)is that your arms will not do the climbing in most cases．They only hold you into the wall so that your legs can push you upward．The closer you are to the wall, the easier it is to climb．

　　Rock climbing may sound too extreme but it is really an amazing exercise and mentally challenging, too．

1．What are the types of rock climbing?(No more than 6 words．)

_____________________

2．Why should rock climbers always have 3 points touching the wall?(No more than 12 word．)

_____________________

3．what’s the main use of the arms when climbing?(No more than 7 words．)

_____________________

4．What can be the best title for the passage?(No more than 2 words．)

_____________________

　
E　　
As a result of pollution , Lake Erie , on the borders of the USA and Canada, is now without any living things.　　
Pollution in water is not simply a matter of “poisons” killing large numbers of fish overnight. Very often the effects of pollution are not noticed for many months or years because the first organism(生物体 ) to be affected are either plants or plankton. But these organisms are the food of fish and birds and other creatures. When this food disappears, the fish and birds die too. In this way a whole food chain can be wiped out, and it is not until dead fish and water birds are seen at the river’s edge or on the sea shore that people realize what is happening.　　
Where do the substances which pollute the water come form? There are two main sources sewage (污水) and industrial waste. As more detergent (洗涤剂 ) is used in the home, so more of it is finally put into our rivers. lakes and seas. Detergents harm water birds dissolving the natural substances which keep their feathers waterproof. Sewage itself, if not properly treated, makes the water dirty and prevents all forms of life in rivers and the sea from receiving the oxygen they need. Industrial waste is even more harmful since there are many highly poisonous things in it, such as copper and lead(铅 ).　　
So , if we want or stop this pollution , the answer is simple: sewage and industrial waste must be made clean before flowing into the water. It may already be too late to save some rivers and lakes, but others can still be saved if the correct action is taken at once.　　
72. Pollution in water is noticed _____. 　　
A. when the first organisms are affected    B. when a good many fish and birds die 　　
C. when poisonous things are poured into water      　　
D. as soon as the balance of nature is destroyed 　　
73. The living things die because there is no ____ in the lake or river.  　　
A. water          B. fish               C. poison           D. oxygen 　　
74. Which of the following is harmful according to the passage? 　　
A. Organisms                             B. Plants and plankton in the water     　　
C. Waste water from cleaning   D. Industrial waste made clear before flowing into the water 　　
75.The way to stop water pollution is _______.　　
A. realize the serious situation clearly 　　
B. put oxygen into the river 　　
C. make the waste material harmless before flowing into the water 　　
D. make special room in the sea for our rubbish　　

75.Is ____ necessary to complete the design before National Day?

A. this　　　　　 B. that　　　 C. it　　　　　　 D. he　　　

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