题目内容
B
When people lose legs after accidents or illnesses, emergency care and artificial limbs（假肢）often allow them to walk again. Newts （蝾螈） in the same situation, on the other hand, can grow limbs back on their own! Scientists have known for a long time that certain animals can re-grow limbs, but they haven’t quite figured out how these creatures do it.
Researchers have now come up with some new ideas. Their work may give people the ability to re-grow lost limbs. The researchers started with two simple experiments：when you cut a newt’s leg at the ankle, only the foot grows back；when you cut off a leg at the very end, the whole leg grows back. In both cases, the re-growth begins with stem cells. Stem cells can develop into nearly any type of cell in the body.
How do a newt’s stem cells know when to grow only a foot and when to re-grow a whole leg?
This question relates to another mystery. In newt’s, a cut-off leg will grow back only if the nerve bundle（神经束）in it also grows back , but if something prevents the nerve bundle from growing, the stem cells at the wound won’t re-grow a new leg.
In its study, a British team focused on a protein called n-AG. When the team prevented nerves in a limb from growing, but added the n-AG protein to stem cells in the limb, the limb still re-grew. That protein seems to guide limb re-growth. People have proteins that are similar to n-AG. Further research into these materials may someday help human limbs recover by themselves.
40. In the experiments, the researchers cut off a newt’s foot or leg to find out _____.
A. what stem cells were B. whether they would grow back
C. how long it would take to re-grow D. how they would re-grow
41. A newt will re-grow its leg if _____.
A. its ankle was cut off but the nerve bundle was good
B. its leg was cut off and the nerve bundle stopped growing
C. its leg was cut off and the nerve bundle could grow back
D. its ankle and the nerve bundle were cut off
42. What do the underlined words “these materials” refer to?
A. Nerve bundles and proteins. B. Proteins similar to n-AG.
C. Stem cells and proteins. D. Stem cells and nerve bundles.
43. The first sentence of the passage _____.
A. acts as a lead–in B. shows where researchers got their new ideas
C. states the author’s opinion D. describes the result of researchers’ studies
40---43 DCBA
解析
B
When I was about 10 one day, I was walking down the street with my mother. She stopped to speak to Mr. Lee. I knew I could see Mr. Lee anytime around the neighborhood, so I just stood there. After we passed him, my mother stopped and said something unforgettable, “You let that be the last time you ever walk by somebody you know without opening your mouth to speak, because even a dog can wag its tail when it passes you on the street.” That sentence sounds simple but it made me become who I am.
At work, I used to say hello to the president of the company and ask him how our business was doing. But I also spoke to the people in the café and people who cleaned the buildings, and asked them how their children were doing, for every single person deserves to be accepted, no matter how humble(低微的) they are. I remember that after a few years of passing by the president, I had the courage to ask him for a chat. We had a great talk. At some point, when I asked him how far he thought I could go in his company, he said that if I wanted to, I could get all the way to his seat.
I’ve become vice-president, but that hasn’t changed how I treat people. I speak to people wherever I am. Speaking to people creates a pathway into their world, and it lets them come into mine, too.
The day you speak to someone who has his head down and then see him lift it up and smile, you will realize how powerful it is just to open your mouth and say hello.
【小题1】What is the best title for this passage?
| A．The Power of Being Talkative |
| B．My Mother’s Influence on Me |
| C．The Power of Saying hello |
| D．My Way to Become Vice-President |
| A．the writer didn’t know Mr. Lee |
| B．the writer didn’t say hello to Mr. Lee on that occasion |
| C．the writer didn’t get along well with his mother |
| D．the writer’s mother stopped to say hello to everyone she met |
| A．The writer didn’t say hello to everyone in the company. |
| B．The writer made a very good impression on the president of the company. |
| C．The president of the company thought the writer was much better than him. |
| D．The president of the company actually didn’t like the writer at all. |
| A．is a way to get what he wants |
| B．has become a habit and a way of life. |
| C．is a way to show respect for his mother |
| D．is important in making him remembered. |
| A．make our world much better |
| B．make people much happier every day. |
| C．help people understand each other better |
| D．help people work much better |
uminates mine. We write long letters in which we often discover our strangest selves. Each of us appears, sometimes in a funny way, in the other’s dreams. She and I agree that, at certain times, we seem to be parts of the same mind. In my most interesting moments, I often think: “Yes, I must tell…” we have never met.