题目

如图所示，一艘测量船将一束超声波垂直向海底发射，测出从发射超声波到接收反射回波所用时间是4s，巳知声音在水中的传播速度是1500 m/s。问：这处海底深度是多少？    答案：解析:略 14．假定你是李华，下面四幅图描绘了发生在你上学路上的一件事情，请根据图片内容用英语写一篇短文．I was walking to school this morning when I caught sight of an old woman with a walking stick lying on the ground．I quickly ran over to help her up and asked her what waswrong with her．She told me she slipped and fell due to heart trouble．I was worried and decided totake her to a hospital．And then I went to a department store near the hospital and contactedher family．Soon her son and daughter came to the hospital．They thanked and praised mefor my kindness by writing me a thank-you letter．Although I was late for school today，I felt very proud of what Ihad done．．