问题
单项选择题
This vehicle bounces and glides along the ground ______.
A．at an average speed of 40 miles an hour
B．of 40 miles an hour at an average speed
C．at 40 miles an hour of an average speed
D．of an average speed at 40 miles an hour
答案
参考答案：A
解析：[分析] 固定搭配 at a speed of...表示：以……的速度；at an average speed of 40 miles an hour表示：以平均每小时40英里的速度……；还要注意语序；因此答案为A。