【摘要】：2013六级考试进入了最后的冲刺阶段，语法的知识点是难点和重点，以下是精品学习网特为考生们整理了2013英语六级语法;关系副词与“介词+which”的区别,希望能给广大考生们在复习中作出一点贡献。预祝考生们通过考试!
引导定语从句时where与in which有时可互换，有时不能互换，注意以下几点：
一、关系副词与“介词+which”互换的情形
当“介词+ which”在定语从句中作时间、地点和原因状语时，可以用相应的关系副词when, where和why来替换。
1. when根据情况可以等于in which, at which, on which等。如：
The day when (=on which) she arrived was Thursday. 她到的那天是星期四。
July and August are the months when (=in which) the weather is hot. 七八月是天气很热的月份
这种替换有时出现在非限制性定语从句中。如：
We’ll put off the picnic until next week, when (=by then) the weather may be better. 我们将把野餐推迟到下星期，那时天气可能会好一点
2. where根据情况可以等于in which, at which, on which等。如：
This is the hotel where ( =in which / at which) they were staying. 这就是他们当时住的旅店
Do you remember the place where (=at which) we had lunch? 你记得我们吃午饭的地方吗?
这种替换有时出现在非限制性定语从句中。如：
The Tower of London, where (=in which) so many people lost their lives, is now a tourist attraction. 在伦敦塔中曾有许多人丧命，它现在是旅游胜地
The reason why (=for which) I came here was to be with my family. 我到这里来的原因是要跟我的家里人在一起
My success in business, the reason why (=for which) he dislikes me, has been due to hard work. 他为我在事业上的成功而不喜欢我，我的成功归功于我努力工作
但是，反过来，for which并不一定能换成why。如：
The documents for which they were searching have been recovered. 他们找寻的文件已经找到了。(此句中的for which也不能换成why，理由同上句
二、关系副词与“介词+which”不能互换的情形
1. 有些语境需要用特定的介词来明确其关系，此时若换成关系副词，则会导致意思不明确或句意不能通顺。如：
The ladder on which I was standing began to slip. 我脚下的梯子开始向下滑动。(句中的on which不能换成where，否则意思不明确)
This I did at nine o’clock, after which I sat reading the paper. 九点钟时我做这事，之后我坐着看报。(句中的after which不能换成when，否则意思不明确)
2. 当“介词+which”后面接有被which修饰的名词时，通常不能用关系副词代替。如：
The programme will continue until 1994 by which time $3million will have been spent.
这个项目将持续到1994年。到那时开支将达到300万美元。(句中的by which time不能换成when或where，因为which后跟有它所修饰的名词time
We arrived at noon, by which time the demonstration was over. 我们是中午到的，这时游行业已结束。(句中的by which time不能换成when或where，因为which后跟有它所修饰的名词time