Please be careful when you ______ the crowded street.

来源：学生作业帮编辑：作业帮分类：英语作业时间：2024/05/18 03:42:52

Please be careful when you ______ the crowded street.
这里是否只能填 cross?
可不可以填 are crossing?如果不行,为什么呢?cross是短暂动词吗?

1.当然也可以填are crossing.具体该填哪个完全根据上下文的含义来理解.如果句子强调进行的意味,填are crossing完全可以.而如果表明"总该是如此"的话,cross就更加合适.
2.cross从意思上就能判断它是个延续性动词.
3.更正楼上的说法,when引导的时间从句的动词并没有所谓瞬间/延续的限定,该从句同样也可以用进行时态.它是比较灵活的.
如:He entered the classroom when I was reading books.
4.当然while引导的时间状语从句一定要求其谓语动词是延续性动词,且用进行时居多.

Please be careful when you ______ the crowded street. Be careful when you c_______ the street you must be careful when you （）the street Be careful when you are crossing the street. You must be careful when crossing the street.改为祈使句 Be careful when you walk ____ the street .Be careful when you come____the street,because the traffic 连词成句：cross,be,the,when,careful,you,street Be careful when ( you are ) crossing the street. be careful when you walk ( ) the street,为什么填across be careful when you are crossing the street.可以改写成be careful when crossing street,you must be careful