下列关于信息的传递和电磁波的说法正确的是（  ）

    Charlie was about to climb into bed when he found there was a light on in his garden shed(棚). Then he noticed some people who were busy stealing his things.
    He call the police right away. The policeman asked, “Are there any intruders(闯入者)in your house?” Charlie replied “no” and explained what was happening.
    The policeman said, “All patrol cars(巡逻车) have gone out, and a policeman will go to your house when one is free.”
    Charlie hung up, waited 30 seconds, and then called the police again. “Hello, I just called a short while ago because there were people stealing things from my shed. I want to let you know that they're not a problem anymore because I've just shot every one of them.”
    Charlie then hung up the phone. In five minutes, three patrol cars, nearly twenty policeman and an ambulance arrived at his house. Of course, the police caught the thieves.
    One policeman said, “I thought you said that you shot every one of them!”
    Charlie replied, “I thought you said there were no patrol cars free!”

一个多边形，它的内角和比外角和的4倍多180°，求这个多边形的边数及内角和度数．

如图是测量小灯泡额定功率的实验装置，小灯泡上标有3.8V的字样．

根据首字母提示补全短文

       At some time in your life，you might have a roommate．It is a good idea to share a flat，especially for students or people who have just finished school，because flats are usually expensive．And m____ is not the only reason for having a roommate．Sharing a flat can be fun．

     But life with a roommate can also be a t____ experience．Some experts did a study of college students who shared a room．They found that students who had problems with their roommates were not happy at school and were more likely to get sick than other students．So，how can you l____  with a roommate and enjoy it? Here is some advice:

      Being roommates with a friend can be hard. Friends may be different when you stay with them all the time from when you don't see them very o ____．So， before you plan to share a room with a friend，discuss the situation carefully．

      If you decide to share a room with someone you don't know，talk to each other．It's important to be h ____ about your habits and things you hate．

    When you move in with a roommate，make rules．Decide how you will share h ____，such as cleaning，washing and shopping． Will you share food? Is it OK to have guests? And what about loud music?

     Don't get angry at small things that your roommate does．Try to f____  the unhappy things between you and your roommate．No one —including you — is perfect．