题目

Lydia is 14 years old. She lives in a small house with her parents and two brothers, Daniel and Henry. Daniel is 12 years old, and Henry is 9 years old. Daniel and Henry often complain about the small house. They want to live in a big house. Their dream house is very big. In the house, they each have a bedroom, a desk and a computer. In front of the house, there is a big beautiful garden. In the garden, there are some fruit trees. They like eating fruit very much. Behind the garden, there is a swimming pool. They like swimming, too. They can ask their friends to come to their house on weekends试判断下列几个速度中哪个不是瞬时速度（ ）?A．子弹出枪口的速度是800m/s?B．小球第3s末的速度是6m/s?C．汽车从甲站行驶到乙站的速度40km/h?D．汽车通过站牌时的速度7.2km/h?