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问题 单项选择题

某两地的通行必须经过两座桥，第一座桥需要维修的概率为0.05，第二座桥需要维修的概率为0.02，则这两地正常通行的概率为______。

A．0.07

B．0.01

C．0.931

D．0.069

答案

参考答案：C

解析：设A={第一条桥正常通行的概率}，B={第二条桥正常通行的概率}，则P(AB)=P(A)P(B)=[1-P(A)][1-P(B)]=(1-0.05)(1-0.02)=0.931。

单项选择题

One day a rich woman lost her purse with a lot of money in it. So she made a (1) , "If anybody finds my purse and (2) it to me, I’ll give half the money to him."A poor man (3) the purse near a shop. He sent it back to the woman, but the rich woman (4) . "There was an expensive ring in my purse besides money," said the woman, "I won’t give you half the money in my purse until you return it to me." "But I’ve never seen an expensive ring in (5) purse," said the man.They began to quarrel. The man became (6) and took her to a judge. (7) the judge heard what had happened to them, he said to the woman, "I’m sure that you have lost a purse, and there is an expensive ring in it. But there is (8) a lot of money in this purse. So I don’t think it’s yours. (9) some time. Maybe somebody will give your purse back."Then the judge (10) to the man and said, "Take the purse home. If the owner doesn’t come to get it back in two days, it will be yours.

第（8）空应选择（）

A．only

B．truly

C．nearly

D．really
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问答题 简答题

选择货位要遵循哪些原则？
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