阅读下面短文，从短文后所给各题的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。

I used to live selfishly, I should admit. But one moment changed me.

　 I was on my lunch break and had 31 the office to get something to eat. On the way, I 32 a busker(街头艺人)，with a hat in front of him. I had some 33 in my pocket, but I would not give them to him, thinking to myself he would 34 use the money to feed his addiction to drugs or alcohol. He 35 like that type-young and ragged. 36 what was I going to spend the money on? Only to feed my addiction to Coca-Cola or chocolate! I then 37 I had no right to place myself above 38 just because he was busking.

I 39 and dropped all the coins into his 40 , and he smiled at me, I watched for a while. As 41 as it sounds, I expected something more to come from that moment—a feeling of 42 or satisfaction, for example. But nothing happened. 43 , I walked off. “It proved to be a waste of 44 ,”I thought.

On my way home at the end of the 45 , I saw the busker again and he was 46 . I watched him pick up the hat and walk 47 a cafe counter. There he poured the 48 contents into a tin collecting 49 an earthquake fund-raising(募捐) event. He was busking for charity(慈善)！

Now I donate any 　50 I have to charity tins and enjoy the feeling of giving.

31. A. left　　　　 B. cleaned　　　 C. prepared　　　 D. searched

32. A. led　　　　　　　　 　　　　　 B. chose　　　 　 C. saw D. fooled

33. A. chocolate　 B. coins　　　　 C. tins　　　　　 D. drugs

34. A. almost　　　 B. only　　　　 C. rather 　　　 D. still

35. A. acted 　　　 　　　　　　　　 B. looked 　　　 C. sounded D. smelt

36. A. Though 　　　 B. For　　　　　 C. Therefore 　 D. But

37. A. declared 　 B. realized　　 C. expected　 　 D. guessed

38. A. it 　　　　　 B. all　　　　　 C. him　　　　　 D. them

39. A. waited 　　 B. followed　　 C. stopped　　　 D. arrived

40. A. rag 　　　　 B. hat　　　　　 C. pocket　　　　 D. counter

41. A. selfish 　　 B. awkward　　　 C. innocent　　　 D. special

42. A. happiness 　 B. sadness　　　 C. love　　　　　 D. hate

43.A.Disappointedly B.Unfortunately C.Coincidentally D.Comfortably

44. A. words 　　　 B. effort　　　 C. space　　　　 D. money

45. A. moment 　　　 B. day　　　　　 C. break　　　　 D. event

46.A. walking around 　　　　　　　　 B. passing by　　 C. packing up D. running off

47. A. around 　　　 B. in　　　　　 C. behind　　　　 D. to

48. A. chief 　　　 B. basic　　　　 C. actual　　　　 D. total

49. A. by 　　　　　 B. for　　　　　 C. on　　　　　　 D. with

50. A. work 　　　　 B. time　　　　 C. energy　　　　 D. change

When an ant dies, other ants move the dead insect out. Sometimes, the dead ant get moved away very soon—within an hour of dying. This behavior is interesting to scientists, who wonder how ants know for sure—and so soon—that another ant is dead.
One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist. Choe found that Argentine ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead—take me away.”
But there’s a twist to Choe’s discovery. Choe says that the living ants—not just the dead ones—have this death chemical. In other words, while an ant crawls around, perhaps in a picnic or home, it’s telling other ants that it’s dead.
What keeps ants from dragging away the living ants？Choe found that Argentine ants have two additional chemicals on their bodies, and these tell nearby ants something like, “Wait—I’m not dead yet.” So Choe’s research turned up two sets of chemical signals in ants: one says, “I’m dead,” and the other set says, “I’m not dead yet.”
Other scientists have tried to figure out how ants know when another ant is dead. If an ant is knocked unconscious, for example, other ants leave it alone until it wakes up. That means ants know that unmoving ants can still be alive.
Choe suspects that when an Argentine ant dies, the chemical that says “Wait-I’m not dead yet” quickly goes away. Once that chemical is gone, only the one that says “I’m dead” is left. “It’s because the dead ant no longer smells like a living ant that it gets carried to the graveyard, not because its body releases(释放) new unique chemicals after death,” said Choe. When other ants detect the “dead” chemical without the “not dead yet” chemical, they drag away the body.
Understanding this behavior may help scientists figure out how to stop Argentine ants from invading new places and causing problems. Choe would like to find a way to use the newly discovered chemicals to spread ant killer to Argentine ant nests.
The ants’ removal behavior is important to the overall health of the nest. “Being able to quickly remove dead individuals and other possible sources of disease is extremely important to all animals living in societies, including us,” says Choe. “Think about all the effort and money that we invest daily in waste management.”
【小题1】The underlined word “twist” in Paragraph 3 means             .

When an ant dies, other ants move the dead insect out. Sometimes, the dead ant get moved away very soon—within an hour of dying. This behavior is interesting to scientists, who wonder how ants know for sure—and so soon—that another ant is dead.

One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist. Choe found that Argentine ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead—take me away.”

But there’s a twist to Choe’s discovery. Choe says that the living ants—not just the dead ones—have this death chemical. In other words, while an ant crawls around, perhaps in a picnic or home, it’s telling other ants that it’s dead.

What keeps ants from dragging away the living ants？Choe found that Argentine ants have two additional chemicals on their bodies, and these tell nearby ants something like, “Wait—I’m not dead yet.” So Choe’s research turned up two sets of chemical signals in ants: one says, “I’m dead,” and the other set says, “I’m not dead yet.”

Other scientists have tried to figure out how ants know when another ant is dead. If an ant is knocked unconscious, for example, other ants leave it alone until it wakes up. That means ants know that unmoving ants can still be alive.

Choe suspects that when an Argentine ant dies, the chemical that says “Wait-I’m not dead yet” quickly goes away. Once that chemical is gone, only the one that says “I’m dead” is left. “It’s because the dead ant no longer smells like a living ant that it gets carried to the graveyard, not because its body releases(释放) new unique chemicals after death,” said Choe. When other ants detect the “dead” chemical without the “not dead yet” chemical, they drag away the body.

Understanding this behavior may help scientists figure out how to stop Argentine ants from invading new places and causing problems. Choe would like to find a way to use the newly discovered chemicals to spread ant killer to Argentine ant nests.

The ants’ removal behavior is important to the overall health of the nest. “Being able to quickly remove dead individuals and other possible sources of disease is extremely important to all animals living in societies, including us,” says Choe. “Think about all the effort and money that we invest daily in waste management.”

1.The underlined word “twist” in Paragraph 3 means             .

A．an unexpected change                   B．a clear mistake

C．an important key                        D．a shocking conclusion

2.Ants judge whether another one is dead or not depending on            .

A．the sense of taste                       B．the sense of smell

C．the sense of touch                      D．the sense of sight

3.The result of the research can be used to            .

A．kill troublesome pests

B．solve the problem of endangered species

C．prevent further expansion of the ants’ territory

D．keep the balance of nature

4.Why is it important to remove dead individuals?

A．Because it is easier to manage the living.

B．Because it can save money to deal with the waste.

C．Because it can provide more space for the living.

D．Because it can keep the living from suffering disease.

5.What might be the best title of the text?

A．Dead or living? It is easy to judge

B．Pulling away the dead ants is a difficult task

C．Ant nests have great undertaking capacity

D．Leaving it alone or taking it away? Ants feel puzzled