Tom slipped into the house when no one was noticing这句话为什么同过去进行时?是因为when的关系吗?那什么时候用进行时?什么时候不用?为什么这句话不用呢?he had walked three or four miles when he saw a cart,halg-full of hay,by the side of the road.
问题描述：
Tom slipped into the house when no one was noticing这句话为什么同过去进行时?
是因为when的关系吗?
那什么时候用进行时?什么时候不用?
为什么这句话不用呢?he had walked three or four miles when he saw a cart,halg-full of hay,by the side of the road.
答
过去时态+when+过去进行时表示两动作同时发生
when后面的时态领先when前面一个时态
he had walked three or four miles when he saw a cart,halg-full of hay,by the side of the road.为过去完成时态+when过去时态
答
这里强调的是他溜进屋子的那个短暂动作发生的时间点,那个时刻是没有人发现他的,而这个动作很快就结束了.
意思和Tom slipped into the house with nobody's notice.差不多.其实这类似一个伴随状语,说明她动作发生的那一刻是没人注意到的.