1. This is the fastest train there is to Beijing.

2. He is an honest man, as is known to all.

　 He was a foreigner, as I know from his accent.

(3) as 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.

附: 关系代词的省略:

1. 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.(先行词是一个短语)

　 He was proud, which I dislike very much.(先行词是一个句子)

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。

1. He was late again, which made his teacher very angry.

1. The student that was praised at yesterday's meeting is the monitor who is very modest and works very hard .

(C) as & which:

as & which 引导非限制性定语从句的区别：

(1) 位置的不同：

which 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. I met a foreigner in the park yesterday afternoon who could speak Chinese very well.

(4) 一个句子中带有两个定语从句，其中一个定语从句的关系代词是that ,另一个则宜用who, 以免重复. 如：

2.There are several students in our class who are still not sure about the use of attributive clauses.

(3) 当先行词有较长的后置定语时. 如：

1.There is a gentleman who wants to see you .

5.Persons who are quarrelsome are despised.

(2) 在There be 结构中，修饰主语的定语从句宜用关系代词who 指代人. 如：