2016-06-23
xredued04
句型34
in case of…(+n.) "以防;万一";
in case that…"以防，万一……"(谓语动词用一般现在时态或should+动词原形)
[例句]
In case of fire, what should we do?
Please remind me about it in case I forget/should forget. 万一我忘了，请提醒我。
In case (that) John comes/should come, please tell him to wait.
Please take your umbrella in case (that it rains/should rain).带上雨伞，以防下雨。
句型35
unless…"除非，如果不……"(=if…not)
[例句]
I shall go tomorrow unless it rains. 如果不下雨，我明天去。
-Shall Tom go and play football?
-Not unless he has finished his homework. 除非他完成作业，否则不能出去。
I won't go unless he comes to invite me himself.
除非他本人来邀请我，不然我是不会去的。
I won't attend his birthday party unless invited (=unless I am invited). 除非被邀请，否则我不
去参加的生日晚会。
句型36
when引导的从句
when除了用来引导主语从句、宾语从句、时间状语从句、表语从句和定语从句，还有一种用法值得关注，那就是when引导并列分句，意思是"这 时突然;就在那时"，强调另一个动作的突然发生。常用于以下句型中：(1)、主语 + be doing… when…意思是"正在做某事这时……";(2)、主语 + be about to do…when…;(3)、主语+be on the point of (doing) …when…意思是"正要去做某事这时……"
[例句]
One day Chuck was on a flight across the Pacific Ocean when suddenly his plane crashed. 有一天，Chuck正在太平洋上飞行，这时他的飞机突然爆炸了。