how fast does a car run?60 kilometers an hour,60 kilometers in an hour,at 60kilometers anhourat 60 kilometers in an hour 选择 说出理由
问题描述：
how fast does a car run?60 kilometers an hour,60 kilometers in an hour,at 60kilometers anhour
at 60 kilometers in an hour 选择 说出理由
答
at 60 kilometers in an hour
在一小时内行驶多远
这没什么疑问
答
加上介词in，表示在一个小时中。最好的说法是60 kilometers per hour,表示每小时60公里的意思
答
选60 kilometers an hour,A.
at 用于“以……的速度”时,后面要有“速度”,at a speed of
因为它问的是“how fast does a car run?”强调fast,而B,强调一个小时走了60km