应该是FALLING 额,去查了,你自己看吧。。。She watched the children crossing/as they crossed the road, ie observed them as they did it (but not necessarily from start to finish). 她看着孩子们横过马路(但不一定注视全过程). * She watched the children cross the road, ie observed the action from start to finish. 她看着孩子们横过了马路(注视着全过程).