Don't stick your head out of the bus windows when the bus drivng 为什么正确答案是when it is running
问题描述：
Don't stick your head out of the bus windows when the bus drivng 为什么正确答案是when it is running
答
因为只能说 某人 drive bus.如果 bus作主语,则可以说bus is running表示车在开.