so long as和as long as有什么区别

　　区别是用于肯定比较的时候只能用as long as，不能用so long as。也就是说和......一样长时，只用as long as，不用so long as。
　　例如：
　　Springboard. Scientists achieved the simplest quantum states of motion with this vibrating device, which is as long as a hair is wide.
　　科学家们利用这种振荡设备获得了最简单的运动量子态，该设备的长度只有一根头发宽。
　　The list of areas which need a shake-up is as long as it is familiar.
　　需要改革所涉及的经济领域也是大家熟悉的。
　　The Valles Marineris is as long as the USis wide, and in places reaches 10km deep.
　　水手山谷系（火星上的一个峡谷系）和美国国土同宽，有的峡谷深度高达10千米。
　　以上句子不能换。
　　但是表示只要或者否定的比较是可以互换的。
　　如：
　　As long as your competitor is up for the challenge, you might as well go for it.
　　只要你的竞争者可以挑战，那么你也可以去为奖学金而奋斗。
　　=So long as your competitor is up for the challenge, you might as well go for it.
　　My kite's tail is not as long as yours.
　　我的风筝滑尾巴没有你的长。
　　=My kite's tail is not so long as yours.

一、as long as和so long as均可表示“只要”，用于引导条件状语从句，两者没什么区别。如：
1.I don’t care so [as] long as she lets me be with her son. 只要她让我和她儿子在一起，我不在乎。
2.You can take my car as [so] long as you drive carefully. 你可以用我的汽车，只要你小心点儿开。

3.You may use my dictionary as [so] long as you don’t keep it too long. 只要使用时间不太长，你可以用我的词典。

二、但是，当 as long as 用于本义表示“与……一样长”时，与 so long as 在用法上是有区别的，即 as long as 可用于肯定句或肯定句，而 so long as 只用于肯定，不用于肯定句。如：

1.It took three times as long as I had expected.
这件事比我预料的多花了两倍的时间。
2.It didn’t take as [so] long as I expected.
花的时间比我预料的短。