【单选题】听力原文: When you turn on the radio, you hear an advertisement. When you watch television, you hear and see an advertisement. If you turn the pages of a newspaper or magazine, again you find an advertise...
【简答题】When you hear two shouts or whistles,you know that people will come to help you.18. When you hear two shouts or whistles,you know that people will come to help you.