1.用于指距离,表示“直到……为止”之意时,as far as既可用于肯定句,也可用于否定句,但so far as只能用于否定句中.例如：We went as far as Lion Rock Tunnel.我们一直走到狮子山隧道公路那儿.
They did not go as far as the others.他们没有像其他的人走得那么远.
（此句的as far as可以改作so far as）
（二）在表示“直到……程度”之意的借喻说法中,as far as和so far as都可使用,但前者不及后者用得普遍.例：she went so far as （or as far as） to call him a coward.她甚至骂他是儒夫.
（三）在表示“就……而论”之意时,as far as和so far as可互换使用.例：As （or So） far as I koow,she will be away from Macao for two months.
据我所知,她将要离开澳门两个月.
As （or So） far as my knowledge goes,there is no such word in English.
据我所知,英语里没有这样一个字.
(四）在表示“只要”、“尽……所能”之意时,应用as far as,不用so far as.例：I'll do my utmost to help you as far as I can.
只要可能,我一定竭尽全力来帮你.Eric Partridge在他编著的Usage and Abusage一书中写道（第44页）,在用作比喻意义的叙述句里,so far as比as far as用得普遍,他举了这样一个例子：so far as I can see,your idea is admirable.
2.一、在表示during the whole time that(长达……之久)或while(只要)的含义时,往往用as long as.如:
1.they all continued their regard for me as long as they lived.他们毕生都在关心着我.
2.For almost as long as Juanita could remember,adding,subtracting,multiplying,and dividing seemed as easy as breathing,and as natural.在胡安妮塔的记忆中,加减乘除对自己来说早就是如同呼吸一样简单而自然了.
3.As long as there is life there is hope.留得生命在,不怕没希望.
二、在表示on condition that,provided that或if(只要,如果)的含义时,用as long as或so long as的情况均很常见.如:
1.You can go out,as / so long as you promise to be back before 11 o'clock.你可以出去,只要你答应在11点以前回来.
2.I'll accept any job as / so long as I don't have to get up early.只要不必早起,任何工作我都可以接受.
3.So / As long as electric current flows through a wire,there is a potential difference.只要有电流通过,导线就有电位差.
4.these stories reinforced the idea that all individuals,no matter how poor,were capable of becoming wealthy so / as long as they were hardworking.这些故事强化了一种思想,那就是,所有人,不管有多穷,只要勤劳,都能变富有.
三、在表示since,considering that(既然,因为)的含义时,多用as long as.如:
1.As long as we've driven this far,we might as well go on.我们既然已经驶得这么远了,就不妨继续前进.
2.As long as you are here,go on.你既然已经来到这里了,就干吧.
3.As long as you are going,I'll go too.既然你要去,那么我也去.
四、有时,as / so long as与if only同义,由它引导的状语分句可不依附主句而单独使用,表示说话人的希望、愿望或遗憾心情等.如:
—It's said it's going to turn colder and freeze later on.听说过些时候天气要变冷,有冰冻.
—As long as it doesn't spoil the weekend.(=I hope that it doesn't spoil the weekend.) 只要不把周末弄糟了就没事.
五、在用as / so long as连接的从句中,当其谓语为be,而主语和主句的主语相同时,则从句的主语和be可以省略.如:
I'm sure we are safe as long as(we are) in his care.我深信只要在他的保护下,我们就会平安无事.
