YOU MUST have been driving at seventy miles an hour.这里去掉AT可以吗

问题描述:

YOU MUST have been driving at seventy miles an hour.这里去掉AT可以吗
at的作用是什么

不能,at seventy miles an hour 以每小时七十英里的速度 at 在这里表示以·····速度句子:你肯定一直在以每小时七十英里的速度开车.去掉at,语义发生变化,seventy miles an hour.,每小时七十英里句子:你必须一直...i was doing eighty when i overtook you 怎么不加at