●as & which:
as & which 引导非限制性定语从句的区别： ①位置的不同：
Which（放句中） 引导的定语从句只置于所限制的句子后；as 位置较灵活，也就是说as可置于所限制的句子前面；插在句子中或放在句子后。如： 1. He was late again, which made his teacher very angry.
2. Jack, as you know, is an honest man. 或Jack is an honest man , as you know. 或As you know, Jack is an honest man. ②先行词的不同：
as引导非限制性定语从句时，其先行词多为一个句子； which引导非限制性定语从句时，其先行词可以是一个词，一个短语或一个句子。 He was proud, which his brother never was. （先行词是一个词）
She was very patient towards the children, which her husband seldom was. He was proud, which I dislike very much.（先行词是一个句子） He is an honest man, as is known to all.
He was a foreigner, as I know from his accent. ③as 一般译为\正如\就像\，\这一点\
as we all know；as you know; as is known to all; as you see; as we can see; as has been expected; as we have imagined.
·The same…as 与the same…that 的区别
The same…as 指的是同一类事物, 例如 She bought the same shirt as I wear.
The same…that 指的是同一个事物，例如
The police found the same car that I lost last week.
高中英语语法定语从句总结全
