we mustn't talk to a driver when he ___(drive)

问题描述:

we mustn't talk to a driver when he ___(drive)

is driving 当某件事情正在发生的时候我们不能做什么事情。这里是当司机正在开车的时候我们不要跟他讲话。

we mustn't talk to a driver when he is driving.
当司机正在开车时,我们不能和他交谈。

drives
主将从现,条件句.