the way (in which)the words are used is very important.为什么不是in that,which

题目

the way (in which)the words are used is very important.为什么不是in that,which

答案

1、关于which和in which
因为在定语从句中 in which是use的方式状语,所以单独的名词或代词不能作状语,而in which这一介宾短语结构恰恰可以作方式状语,故此要用 in which（in必须保留）,但美式英语中经常把in which省掉.
2、关于in which和in that
理论上讲in which和in that本质上没有什么不同,但英语中习惯于把in which用在类似于您提到的这样的定语从句中（which兼作方式状语中介宾短语中的宾语）,而偏偏习惯于把in that当成because来理解,也就是说in that()这个介宾短语作补语.本质上讲,that后面的内容是that的同位语,in that的本义就是”在那个事情上“,例如：She was fortunate in that she had friends to help her（因为有朋友帮她所以她很幸运,在有朋友帮她这件事情上她是幸运的）