问题 选择题

编号1,2,3,4,5,6的六个球分别放入编号为1,2,3,4,5,6的六个盒子中,其中有且只有三个球的编号与盒子的编号一致的放法种数有(  )

A.20

B.40

C.120

D.480

答案

从6个盒子中选出3个,填入3个球,使三个球的编号与盒子的编号一致,有 C63 种方法,

剩余的3个盒子的编号与三个球的编号不一致,有2种方法,

故有且只有三个球的编号与盒子的编号一致的放法种数有C63×2=40种,

故选 B.

阅读理解

阅读下面的短文,请根据短文后的要求将答案答题(请注意问题后的要求)。

     The Internet has opened up a whole new online world for us to meet, chat and go where we've never been before. But just as in face-to-face communication, there are some rules of behavior that should be followed when online.

     The basic rule is simple: treat others in the same way you would want to be treated. Imagine how you'd feel if you were in the other person's shoes. For anything you're about to send: ask yourself, "Would I say this to the person's face?" If the answer is "no", rewrite and reread. Repeat the process till you feel sure that you'd feel comfortable saying the words to the person's face.

     If someone in the chat room is rude to you, your instinct(本能反应)is to fire back in the same manner. But try not to do so. You should either ignore the person, or use your chat software to block their messages. If it was caused by disagreement with another member, try to fix the situation by politely discussing it. Remember to respect the beliefs and opinions of others in the chat room.

     If you do decide to tell someone in the chat room about a mistake, point it out politely. At the same time, if you find you are wrong, be sure to correct yourself and apologize to those that you have offended.

It is not polite                      such as their age, sex, and marital status. Unless you know the person very well, and you are both comfortable with sharing personal information, don't ask such questions.

1. What's the best title of the passage? (Please answer within 10 words.)

                                                                                                                                                          

2. Why should we ask ourselves "Would I say this to the person's face?" when we are to send a message online? (Please answer within 20 words.)

                                                                                                                                                            

3. Please fill in the blank in the last paragraph to complete the sentence. (Please answer within 10 words.)

                                                                                                                                                           

4. Which rule do you think is the best? Why? (Please answer within 30 words.)

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5. Translate the underlined sentence in the first paragraph into Chinese.                            

                                                                                                                                                             

单项选择题