题目

 小船在静水中的速度为3m/s，它在一条流速为4m/s，宽为150m的河流中渡河，则小船（     ）A. 运动轨迹不可能垂直河岸        B. 渡河时间的最小值为50sC. 小船渡河时间的最小值为30s     D. 渡河时间为50s，到对岸时，它已被冲下100m 答案：AB听下面一篇短文，短文后有5个小题，从题中所给的A、B、C三个选项中 选出最佳选项。1. Where did Sophie and Jason go on holiday? A. They went to Paris. B. They went to Hainan.C. They went to Hawaii. 2. Where did they swim with dolphins? A. In a river. B. In the sea. C. In a pool. 3. What did they do before they went into the water? A. They had breakfast.B. They read a book about dolphins.C. They watched a video about dolphins. 4. How long did they swim with dolphins that day? A. One hour. B. Two hours.C. Three hours. 5. For what special reason did they go on holiday?A. For their 60th birthday. B. For the New Year.C. For being married for 60 years.