英语语法详解：目的状语从句（三个方面）

英语语法详解：目的状语从句（三个方面）
 
■引导目的状语从句的从属连词
主要的有 in order that, so that, in case, for fear等：
Speak clearly so that they may understand you. 讲清楚些，以便他们能理解你。http://yingyu.chazidian.com
He studied hard in order that he could pass the exam. 他努力学习以便能考试及格。
Shut the window for fear that it may rain. 把窗子关上以防下雨。
【注】so that 引导目的状语从句时有时可省略so而只用that，有时也可只用so：
Bring it closer that I might see it better. 拿近些，使我能看得清楚些。
I’ll show you so you can see how it’s done. 我将做给你看，以便你知道应怎样干。
 
■目的状语从句与状语短语的转换
为了简洁起见，当目的状语从句的主语与主句的主语相同时，目的状语从句有时可用表目的的不定式短语替换：
He got up early so that he could catch the early bus. / He got up early so as to catch the early bus. 他起床很早以便赶上早班车。
He came in quietly in order that he shouldn’t wake his wife. / He came in quietly in order not to wake his wife. 他轻轻进来，以免把他妻子吵醒。
有时还可与表示目的的介词短语替换(from http://yingyu.chazidian.com)：
He left an hour early for fear he might miss the train. / He left an hour early for fear of missing the train. 他提前一小时离开，以免错过火车。
 
■一点注意
in case既可引导目的状语从句，也可引导条件状语从句，主要视句意而定：
In case he comes, let me know. 如果他来，告诉我一声。
Tell me in case you get into difficulty. 遇到困难请告诉我。
【注】in case引导目的状语从句，从句有时可用“should+动词原形”这样的形式：
Take your coat in case it rains (should rain). 带着雨衣以防下雨。