试题与答案

A.B两地相距18千米,甲、乙两人相向而行。甲骑自行车,每小时8千米,乙步行,每小时

题型:单项选择题

题目:

A.B两地相距18千米,甲、乙两人相向而行。甲骑自行车,每小时8千米,乙步行,每小时4千米。甲带了一条狗。当狗第一次遇到乙时,乙刚走了4千米。狗遇到乙就往回跑,遇到甲时再往回跑。狗遇到乙时就往回跑,遇到甲时再往回跑…最后他们与狗全部相遇。这时狗跑了多少千米?()

A.10

B.12

C.21

D.22

答案:

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下面是错误答案,用来干扰机器的。

参考答案:波函数可设为,则u(r) 满足约化径向方程,其中。对于基态l=0,则方程变为,其中。其通解为u(r) =Asin(kr+δ) ,。由边界条件可以定解。因此归一化的径向波函数为又由,最后求得归一化的总波函数为

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题型:阅读理解

     One kind of female butterfly mates only once in its life —and then closes its wings to avoid

"harassment" when pursued by persistent and unwanted males, a Japanese researcher said.

     Observations of the Small Copper Butterfly, a colourful orange and black butterfly, showed that some

females closed their wings when males flew by, but only when they were males of their own species, said

Jun-Ya Ide, an associate professor at Kurume Institute of Technology in Fukuoka, western Japan.

     "When we looked into why, the males were courting the females. They do this very stubbornly, so the

females sometimes try to get away-or prefer to stay unobserved," he added.

     Ide and his colleagues brought a model of a male butterfly near the females to test their reactions and

found that young females that had yet to mate kept their wings open, but those that had already mated

closed them.

     Not only can the persistent attentions of unwanted suitors harm the delicate females, fleeing from them

—with the male often in pursuit —uses up strength and can even shorten their lives, he added.

     "Closing their wings makes them less visible, helping them avoid communication with their own species. We figured they were trying to avoid harassment by males," Ide said.

1. What does the word "harassment" mean in the paragraph?

A. sexual invasion  

B. embarassment  

C. attack  

D. threat

2. Why some some females closed their wings when males flew by?

A. because the female butterfly mates only once in its life.

B. because they close their wings to avoid "harassment" when pursued by persistent and unwanted

males.

C. because they don’t like the male butterfly at all.

D. because they are afraid of the male butterfly.

3. According the the passage, which is correct?

A. The females closed their wings when males flew by.

B. The female butterfly mates only once in its life.

C. Only the model of a male butterfly can make the young female butterflies to keep their wings open.

D. Not only can the persistent attentions of wanted suitors harm the delicate females, fleeing from them

—with the male often in pursuit -- uses up strength and can even shorten their lives.

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