There are two factors(因素) that determine an individual’s(个体的) intelligence. The first is the sort of brain he is born with. Human brains differ considerably, some being more capable than others. But no matter how good a brain he has to begin with, an individual will have a low order of intelligence unless he has opportunities to learn. So the second factor is what happens to the individual-the sort of environment(surroundings) in which he is brought up. If an individual is disabled environmentally, it is likely that his brain will fail to develop and he will never get the level of intelligence of which he is capable.

    The importance of environment in determining an individual’s intelligence can be shown by the case history of the identical(相同的，同胞的) twins were three months old, their parents died, and they were placed in separate foster homes. Peter was raised by parents of low intelligence in a separate community with poor educational opportunities. Mark was brought up in the home of well-to-do parents who had been to college. He was read to as a child, sent to good schools, and given every opportunity to be encouraged intellectually. This environmental difference continued until the twins were in their late teens, when they were given tests to measure their intelligence. Mark’s I.Q. was 125, twenty-five points higher than the average and fully forty points higher than his identical brother. Given equal opportunities, the twins, having identical brains, would have tested at roughly the same level.

68. The best statement of the main idea of this passage is that             .

       A. human brains differ considerably

       B. the brain a person is born with is important in determining his intelligence

       C. environment is crucial(important) in determining a person’s intelligence

       D. persons having identical brains will have roughly the same intelligence

69. According to the passage, the average I.Q. is             .

       A. 85         B. 100          C. 110         D. 125

70. The case history of the twins appears to support the conclusion that             .

       A. individuals with identical brains are seldom tested at the same level.

       B. an individual’s intelligence is determined only by his environment

       C. lack of opportunity blocks the growth of intelligence

       D. changes of environment produce changes in the structure of the brain

71. This passage suggests that an individual’s I. Q.             .

can be predicted at birth           

stays the same throughout his life

can be increased by education             

D. is determined by his childhood

Everyday the mother seems to be busy until 10o’clock at night,____the rest of the

Family have fallen asleep.

        A.that       B.by which time           C.on time         D.whose time

.____he was fired by the company is____he didn’t work hard.

     A. What; because     B. Why; because   C. Why; that    D. That; because

We see the lightning____it happens,but we hear thet hunder later.

        A.the moment                            B.for the moment

        C.at the moment                         D.in a moment

.No sooner____to shine____it clouded over again.

    A.the sun had started;than              B.had the sun started;than

    C.the sun started;when                 D.did the sun started;when

.Is this the very factory____he visited last month?

        A.which                B.that             C.where            D.in which

— Do you have the time?

    — Sorry， I have no watch.

    — ____

A. What a shame!                               B. Thanks anyway.

C. It doesn't matter.                                 D. Why not buy one?

— How about a game of chess?

— ____

A. I agree.          B. Why not?        C. I’d like to.  D. That’s right.

You ____ things about. Look, what a mess in your room!

A. always throw                           B. have always thrown

C. are always throwing                    D. have always been throwing

You have made a few spelling mistakes in your composition, but ____, it is fairly good.

A. on the whole   B. generally speaking  C. above all       D. on one hand