题目内容

---- The novel isn’t easy for Xiao Wang to read, is it?

---- ______.His foreign language is far better than expected.

A.No, it isn’t           B.I’m afraid not.       C.I think so.          D.Yes, it is.

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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

单词(共20小题;每题0.5分,满分10分)

1.The children are doing well a____________ (学业上).

2.Her abilities are not fully a____________ (欣赏) by her employer.

3.They brought back a few s____________ (纪念品) from their holiday in Greece.

4.Her husband’s death left a v____________ (真空) in her life.

5.Kids e____________ (精疲力竭) themselves by running wildly around the park.

6.Crowds poured into the Beijing Worker’s S____________ (体育场) to watch the performance.

7.She knew she hadn’t done enough r____________ (复习) for tomorrow’s exam.

8. With winter a____________ (临近), many animals are storing food.

9. I didn’t want to ask her a lot of e____________ (尴尬的) questions in front of her friends.

10.The singer got an e____________ (热情的) reception at the airport.

11.She’s a very i____________ (印象深刻的) public speaker.

12. “Artificial I____________ (智能)” is a famous science fiction directed by Steven Spielberg.

13. Many modern arts are being displayed in that art g____________ (美术馆).

14. A lot of small companies have to fight for s____________ (生存).

15.The captain gave the order to a____________ (遗弃) the ship since it was sinking fast.

16.The hotel room had a g__________ (美丽的) view over the lake.

17.He first went to France as an e__________ (交换) student from Beijing.

18.The baby was f_________ (害怕) of being left by itself in the house.

19. In general, the bride’s father gave her away at the wedding c____________ (仪式).

20. Is there a good restaurant in the n____________ (周围)?

 

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

 

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