Even if  you are a good high-jumper, you can jump only about seven feet off the ground. You cannot jump any higher because the earth pulls you hard. The pull of the earth is called gravity.

   You can easily find out the pull of the earth. If you weigh yourself, you will know how much gravity is pulling you. 来源：

   Since there is gravity, water runs down hill. When you throw a ball into the air, it falls back down. Because of gravity, you do not fall off the earth as it whirls (旋转) around. 来源：

   Then, can we get away from the earth and go far out into space? Now you can do it, because spaceships have been invented. Then spaceship will go so fast that it can escape (逃出) the earth’s gravity and carry you into space. 来源：

In this passage, the word “gravity” means_______.来源：

   A. the pull of everything.           B. the force of attraction(吸引) among objects.

   C. the force which attracts objects towards the centre of the earth来源：

   D. the force which attracts the earth towards the sun.

When you slip(滑) you always fall to the ground because________来源：

   A. the earth always turns round.                   B. the earth has gravity

   C. the earth’s gravity is greater than your weight.     D. you are careless. 来源：

Gravity is strong that_______

   A. it can throw a ball into the air.           B. it makes you jump only seven feet.

   C. it can let you fly away from the earth.     D. it can keep everything on earth.

Because of gravity,________

   A. water flows everything.            B. we can go everywhere by ship. 来源：

   C. water always flows downwards.     D. fish can live in water.

We can get away from the earth by spaceship because________

   A. the spaceship goes very fast.       B. the earth can’t pull the spaceship.

C. the spaceship has a strong force.    D. the spaceship can jump higher than others.

   
D
When a storm is coming, most people leave the area as quickly as possible and head for safety…But there are a few people who will get into their cars and go straight for the center of the storm．These people are willing to risk (冒…危险) being killed by floods or 100-Kilometer- an-hour winds for the excitement of watching the storm close up．
“Storm chasing (追逐)”is becoming an increasingly popular hobby (喜好) ，especially in the Midwest of the United States, where there are frequent storms between March and July．A storm chaser begins the day by checking the Internet for the latest weather reports, and then drives up to l,000 kilometers to where the storm will be and waits for it to develop．
Although anyone can do it，storm chasing is extremely dangerous．The power of a big storm  can throw a cow into the air or destroy a whole house in seconds．Storm chasers are also often hurt in accidents caused by driving in a heavy rain．If you are a beginner, it is much safer to join a group for storm - chasing vacations during the storm season．
Even then，storm chasing is not all adventure and excitement．“Storm chasing is 95％driving，”says Daniel Lynch，who spends most of his summer storm-chasing．“Sometimes you
Can sit around for hours waiting for something to happen，and all you get is blue sky and a few light showers.”
However，for storm chasers，it is all worth it. “When you get close to a storm，it is the most exciting sight you will ever see in your life，”says Jasper Morley．“Every storm is an example of the power of nature．It is the greatest show on Earth．”
57．For storm chasing，the first thing storm chasers do is to       ．
A．head straight for the center of the storm   
B．get into the car for safety
C．wait patiently for the storm to develop
D．collect information about a coming storm
58．Beginners of storm chasing are advised_______
A．not to drive in a heavy rain   
B．to do it in an organized way
C．not to get too close to a storm
D．to spend more time on it in summer
59．By saying“it is all worth it”in the last paragraph，the author means that______
A．storm chasing costs a lot of money
B．storm chasing is worth hours of waiting
C．efforts in storm chasing are well paid
D．a storm presents the greatest show on Earth
60．What can we learn from the text?
A．Sometimes storm chasers get nothing but disappointment． 
B．Many storm chasers get killed in the storms．
C．Storm chasing is becoming popular around the world．
D．Storm chasing is only fit for young people

Even if we have an extremely healthy diet and lifestyle, the human body is programmed to wear out at a maximum of about 120 years, and usually less. We all have a biological clock inside us which determines the moment when our organs cease to function properly. This is because our cells have stopped renewing themselves and our body can no longer repair itself. This is also the moment when we are more likely to begin to suffer from the diseases of old age such as arthritis and Alzheimer’s. However, rapid advances in DNA research are beginning to throw light on the secrets of the ageing process. By the end of this century we could literally have the power of life over death.
Although it has long been accepted that humans have a fixed lifespan, it is also a fact that certain other organisms, such as reptiles and amphibians, appear to live indefinitely. The only reason we do not see 500-year-old alligators is because in the wild their lives are always in danger, from man, from pollution and from other animals. When they are kept in zoos they do not seem to age at all after they are fully grown. The same is true of some species of fish, which grow indefinitely and show no signs of ageing. The existence of animals with no fixed lifespan seems to indicate that an age gene really does exist. It is this gene which scientists are searching for, which may delay or repair damage to the body caused by ageing.
Another new area of research involves the oxidation（氧化） theory, which says that ageing is caused by the same process that makes iron rust. In controlled experiments, the lifespans of certain animals were shown to be lengthened with anti-oxidants; for example, the lifespan of mice can be increased by 30%. Antioxidants are already being used in face creams and other cosmetics, and they are likely to play an important part in keeping people physically young.
Perhaps the most immediate advance we are likely to see in the battle to halt（停止）the ageing process will be organ replacement. By the year 2020 it is likely that we will be replacing injured bones or even organs like livers and kidneys with ones “grown” in laboratories. By 2050 perhaps every organ in the body, except the brain, will have become commercially available. Recent experiments also show that it may one day be possible to “grow” new organs inside our body to replace worn-out ones, something which lizards and alligators already do.
Suddenly immortality（不死，不朽） seems within reach. We can begin to imagine a future where we are born, we grow to maturity, but we never grow old and die. But do we really want to live forever?
【小题1】 When all humans reach a certain age,         .

D

When I was growing up, I was embarrassed to be seen with my father. He was badly crippled (跛脚), and when we would walk together, his hand on my arm for balance, people would stare, I would be ashamed of the unwanted attention. If ever noticed or bothered, he never let on.

It was difficult to walk together—and because of that, we didn’t say much as we went along. But as we started out, he always said, “You set the pace. I will try to follow you.”

Our usual walk was to or from the subway, which was how he got to work. He went to work sick, and even in bad weather. He almost never missed a day, and would make it to the office even if others could not. It was a matter of pride for him.

When snow or ice was on the ground, it was impossible for him to walk, even with help... Such times my sister or I would pull him through the streets of Brooklyn, N.Y., on a child’s sleigh to the subway entrance. Once there, he would try to grasp handrail until he reached the lower steps that the warmer tunnel air kept ice free. In Manhattan the subway station was the basement of his office building, and he would not have to go outside again until we met him in Brooklyn on his way home.

When I think of it now, I am surprised at how much courage it must have taken for a grown man to suffer from shame and disability. And I am also surprised at how he did it—without bitterness or complaint.

He never talked about himself as an object of pity, not did he show any envy of the more fortunate or able. What he looked for in others was a “good heart”, and if he found one, the owner was good enough for him.

Now that I am older, I believe that is a proper standard by which to judge people, even though I still don’t know exactly what a “good heart” is. But I know the times I don’t have one myself.

He has been away for many years now, but I think of him often. I wonder if he sensed my reluctance to be seen with him during our walks. If he did, I am sorry I never told him how sorry I was, how unworthy I was, how I regretted it. I think of him when I complain about my troubles, when I am envious of another’s good fortune, when I don’t have a “good heart”.

17. How did the man treat his father when he was young?

A. He helped his father happily.

B. He never helped his father.

C. He helped his father, but not very happily.

D. He only helped his father take a walk after supper.

18. As a disabled man, his father____.

A. didn’t work very hard

B. didn’t go to work from time to time

C. hated those who had good fortune

D. was happy and satisfied, and never lost hope

19. What does the underlined word “reluctance” mean in the article? It means ____.

A. anger                     B. sadness            C. happiness                D. unwillingness

20. How did the father get to work usually?

A. By subway.              B. By bus.            C. By wheelchair.         D. By bike.

D

    When a storm is coming, most people leave the area as quickly as possible and head for safety…But there are a few people who will get into their cars and go straight for the center of the storm．These people are willing to risk (冒…危险) being killed by floods or 100-Kilometer- an-hour winds for the excitement of watching the storm close up．

    “Storm chasing (追逐)”is becoming an increasingly popular hobby (喜好) ，especially in the Midwest of the United States, where there are frequent storms between March and July．A storm chaser begins the day by checking the Internet for the latest weather reports, and then drives up to l,000 kilometers to where the storm will be and waits for it to develop．

    Although anyone can do it，storm chasing is extremely dangerous．The power of a big storm  can throw a cow into the air or destroy a whole house in seconds．Storm chasers are also often hurt in accidents caused by driving in a heavy rain．If you are a beginner, it is much safer to join a group for storm - chasing vacations during the storm season．

    Even then，storm chasing is not all adventure and excitement．“Storm chasing is 95％driving，”says Daniel Lynch，who spends most of his summer storm-chasing．“Sometimes you

Can sit around for hours waiting for something to happen，and all you get is blue sky and a few light showers.”

    However，for storm chasers，it is all worth it. “When you get close to a storm，it is the most exciting sight you will ever see in your life，”says Jasper Morley．“Every storm is an example of the power of nature．It is the greatest show on Earth．”

    57．For storm chasing，the first thing storm chasers do is to        ．

           A．head straight for the center of the storm   

           B．get into the car for safety

           C．wait patiently for the storm to develop

       D．collect information about a coming storm

    58．Beginners of storm chasing are advised_______

           A．not to drive in a heavy rain   

           B．to do it in an organized way

           C．not to get too close to a storm

           D．to spend more time on it in summer

      59．By saying“it is all worth it”in the last paragraph，the author means that______

           A．storm chasing costs a lot of money

           B．storm chasing is worth hours of waiting

           C．efforts in storm chasing are well paid

           D．a storm presents the greatest show on Earth

    60．What can we learn from the text?

           A．Sometimes storm chasers get nothing but disappointment． 

           B．Many storm chasers get killed in the storms．

           C．Storm chasing is becoming popular around the world．

           D．Storm chasing is only fit for young people