问题 选择题
在匀强磁场中有一个原来静止的碳14原子核,它放射出的粒子与反冲核的径迹是两个相内切的圆,如图所示.那么碳14的衰变方程为(  )

A.+

B.+

C.+

D.+

答案

答案:D

阅读理解

阅读理解。

    Last week Lu visited England. He stayed with my grandmother. He said it was a strange visit. "I don't

understand,but I frightened (使害怕) your grandmother a lot. When I arrived, I gave her a purse from

Suzhou, she looked in it and asked me to take it back. Then I saw a red spider on the table so I killed it for

her and she seemed very unhappy. Do English people like spiders?"

    "Later we went shopping. Someone was painting a shop front, so there was a ladder. Grandmother

stopped me from walking under it and said I must walk around it. I liked the shops and bought some lovely

rose soap for my mother, a smart umbrella for my father and some new shoes for myself. When we got

back, I put the shoes on the table and opened the umbrella to check if it was all right. Your grandmother

came in and screamed (尖叫)!" 

    "Then I broke a small mirror in the bathroom.Your grandmother's face went white. I felt very sorry.

When I left I gave your grandmother some flowers. She counted and there were l 3. She didn't like it. I

think she was happy l was goin9."

    I explained to Lu, "My grandmother follows the old customs (习俗). You must not give someone an

empty purse or they will have no money. You must not kill a 'money spider' or the same will happen. Also

it is very unlucky to walk under a ladder and to put new shoes on the table.An open umbrella in a house

means someone will die. Breaking a mirror brings seven years' bad luck, and 13 is also a very unlucky

number. You were really making my grandmother very afraid."

1.Why did Lu frighten the writer's grandmother?[ ]

A.Because he could not speak English.

B.Because he did many unlucky things.

C.Because he understood British customs.

D.Because he went shopping in England.

2.What do many British people think of spiders? [ ]

A.They are afraid of them.

B.They keep spiders as pets.

C.They think some kinds of spiders are lucky.

D.They hope to see every kind of spiders in their houses.

3.What did the writer's grandmother feel when she saw the umbrella? [ ]

A.Excited.

B.Angry.

C.Happy.

D.Afraid

4.Which of the following is NOT true according to the passage? [ ]

A.Thirteen is an unlucky number in England

B.People never give purses as presents in England.

C.For most British people,breaking a mirror means bad luck

D.It is very unlucky to walk under a ladder or put new shoes on the table in England.

5.How many wrong things did Lu do altogether? [ ]

A.5

B.7

C.8

D.10

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