A：我冒雨走路回家被淋湿了。（提示-两件事情同时发生在一个人身上）
I got wet walking home in the rain.
解说：When 2 actions occur at the same time , and are done by the same person or thing , we can use v+ing for one of action .
B：为什么要走路？ 你可以打车。（提示-过去）
Why did you walk? You could have taken a taxi.
解说： 因为事实是没打车，所以要用could have done 虚拟语气。
万一他来晚了，给他发个信息.（提示-将来）
Should him come late, send him a message.
解说：Come late (晚到）。should -将来时态的虚拟语气。
当时要不是他抓住我，我就掉下去了。
Had it not been that he grasped me,I should have fallen.
解说：和事实相反，所以用 should have done. Had it not been 是 if it had not been的倒装。
倒装规律： if 从句里有 had , should ,were (谐音何秀华），可以倒转。
我希望我和她一样高。（提示-和事实相反）
I wish I were as tall as her.
解说：和事实相反，所以用were.
