so far as，so long as，as far as，so far as的区别？

so long as 1 只要 既然
He need not step down so long as they support him.
只要他们支持他，他就不必辞职．
2 由于
as far as＝so far as 1 到...那么远
例:The children walked as far as the lake.孩子们一直走到湖边
2 （表示程度 范围）就．．．；尽．．．；至于
例：as far as I know 就我所知
as far as possible 尽可能
（我已尽力了 希望对你有用）

as far as 是"於~而言"的意思

e.g. As far as I am considered, dogs are as dangerous as lions.

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so far as 也有"就~所知"的意思
同时也可以代表"不至於","竟然"
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so long as 是"只要"的意思
与only if相近
也可代换成 as long as

e.g. So long as you come to my party, you will find how interesting it is.

:)