A) 9 years B) 7 years

C) 4 years D) 3 years

38. What most likely made people think about a transcontinental railroad?

A) The possibility of government support for such a task.

B) The need to explore Utah.

C) The need to connect the east coast with the west.

D) The need to develop the railroad industry in the west.

Questions 39-43 refer to the following invoice and letter.

In the warm enclosed waters of farm ponds, conditions are very likely to be lethal for fish when

insecticides are applied in the neighhourhood. As many examples show, the poison is carried in by rains

and runoff from surrounding lands. Sometimes the ponds receive not only contaminated runoff but also a direct

dose as crop-dusting pilots neglect to shut off the duster in passing over a pond. Even without such

complications, normal agricultural use subjects fish to far heavier concentrations of chemicals than would

be required to kill them. In other words, a marked reduction in the poundages used would hardly alter the

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fatal situation, for applications of over 0.1 pound per acre to the pond itself are generally considered

hazardous. And the poison, once introduced, is hard to get rid of. One pond that had been treated with DDT

to remove unwanted shiners remained so poisonous through repeated draining and flushings that it killed

94 percent of the sunfish with which it was later stocked. Apparently the chemical remained in the mud of

the pond bottom.

In some parts of the world the cultivation of fish in ponds provides an indispensable source of food.

In such places the use of insecticides without regard for the effects on fish creates immediate problems.

In Rhodesia, for example, the young of an important food fish, the Kafue bream, are killed by exposure to

only 0.04 parts per million of DDT in shallow pools. Even smaller die, of many other insectiddes would be

lethal. The shallow waters in which these fish live are favorable mosquito-breeding places. The problem

of controlling mosquitoes and at the same time conserving a fish important in the Central African diet has

obviously not been solved satisfactorily.

39.The word "lethal" in the first sentence nearly means ________ .

A) dead B) important

C) fatal D) vital

40.The author's tone in this passage can be best described as _______

A) depressed B) indifferent

C) questioning D) objective

41.According to the passage, which of the following should not be responsible for the presence of insecticides

in ponds?

A) the weather B) human error

C) commoo farming methods D) conditions of farm ponds

42.The author does all of the following in this passage EXCEPT ________

A)give examples B) propose a solution

C) state a problem D) relate causes

43.Which of the following tittles best sums up the whole passage?

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A) The Effects of Insecticides on Fish

B) The Water of Farm Ponds

C)The Cultivation of Fish as Food

D) Saving African Food Supplies

Questions 44-48 refer to the following invoice and letter.

Although April did not bring us the rains we all hoped for, and although the Central Valley doesn't

generally experience the atmospheric sound and lightning that can accompany those rains, it's still important

for parents to be able to answer the youthful questions about thunder and lightning.

The reason these two wonders of nature are so difficult for many adults to explain to children is that

they are not very well understood by adults themselves. For example, did you know that the lightning we

see flashing down to the earth from a cloud is actually flashing up to a cloud from the earth? Our eyes

trick us into thinking we see a downward motion when it's actually the other way around. But then, if we

believed only what we think and we see, we'd still insist that the sun rises in the morning and sets at

night.

Most lightning flashes take place inside a cloud, and only a relative few can be seen jumping between

two clouds or between earth and a cloud. But, with about 2,000 thunderstorms taking place above the earth

every minute of the day and night, there's enough activity to produce about 100 lightning strikes on earth

every second.

Parents can use thunder and lightning to help their children learn more about the world around them.

When children understand that the light of the lightning flashing reaches their eyes almost at the same

moment, but the sound of the thunder takes about 5 seconds to travel just one mile, they can begin to time

the interval between the flash and the crash to learn how close they were to the actual spark.

44.According to the author, in the area of the Central Valley, ________ .

A) rains usually come without thunder and lightning

B) it is usually dry in April

C) children pay no attention to natural phenomena

D) parents are not interested in thunder and lightning

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45.

A) we were taught so by our parents from our childhood

B) we are deceived by our sense of vision

C) it is a common natural phenomenon

D)it is a truth proved by science

46.What is TRUE about lightning according to the passage?

A) Only a small number of lightning flashes occur on earth

B) Lightning travels 5 times faster than thunder.

C) Lightning flashes usually jump from one cloud to another

D) There are far more lightning strikes occurring on earth than we can imagine.

47.The word "activity"(Para. 3, Line 4) is most closely related to the word(s) .

A) "cloud" "B) lightning strikes"

C) "lightning flashes D) "thunderstorms"

48.It can be concluded from the passage that _________ .

A) we should not believe what we see or hear

B) things moving downward are more noticeable

C) people often have wrong concepts about ordinary phenomena

D) adults are not as good as children in observing certain natural phenomena

Questions 49-53 refer to the following invoice and letter.

Man lives in communities. His social existence restricts his flexibility in certain directions and

extends it in others. Society imposes on him some limitations. People do not all engage in the same activities.