be surprised to do sth与be surprised at的区别
意思都不一样了!
过去进行时态构成：主语+ was____/___were__+___doing__sth+时间状语
常用的时间状语：常与__ago__,_yesterday___,__last night___,__before___等连用,或者用另一动作来表示过去的时间
She _was__in the bed while the others_were all working__(all,work)in the fields at that time