一、用法区别
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 可用于肯定句或否定句，而 so long as 只用于否定句，不用于肯定句。
1、He will be all right so long as you don't touch his sore spot.
只要你不提起他的伤心事，他是没有什么的。
2、He has been on a diet for as long as any of his friends can remember
在朋友的记忆中，他一直都在节食。
二、读音不同
as long as：英 [æz lɔŋ æz]；美 [æz lɔŋ æz]
so long as：英 [səʊ lɔŋ æz]；美 [soʊ lɔŋ æz]
三、引导条件状语从句
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。
1、He paused enough to consider the options but never so long as to lose the initiative.
他停顿了一会儿权衡自己有哪些选项，但并没有久到丧失主动权。
2、As long as I deliver the goods, my boss is very happy.
只要我做好本职工作，我的老板就很高兴。
扩展资料
近义词：if only、so as
一、if only
英 [if ˈəunli] 美 [ɪf ˈonli]
adv.只要;但愿
If only I could get some sleep, I would be able to cope.
要是能睡上一会儿，我就能应付了。
二、so as
英 [səʊ æz] 美 [soʊ æz]
adv.只要
It was virtually impossible to synchronise our lives so as to take holidays and weekends together
想让我们的生活步调保持一致好一起去度假和过周末几乎是不可能的事。
比如例句：as long as you are fearless about your future, you will never be disappointed. 这里as long as 换成so long as 是没有任何区别的，都是“只要”的意思。
但是as long as 还可以作为和。。。一样长，而so long as 就不可以。
比如例句：my penis is as long as yours ， 而不是 my penis is so long as yours本回答被提问者和网友采纳
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。