条件状语和原因状语的区别

条件状语和原因状语的区别在于引导词不同。
1. 引导条件状语从句的连词有：

if 的用法。其意为“如果”。
What is to become of me if you go away?
如果你走的话，我的结果将是怎样呢?
unless 的用法。其意为“如果不”、“除非”。
The company won't keep going unless we can get some loan.
除非我们能搞到贷款，否则公司就维持不下去了。
as [so] long as 的用法。其意为“如果”、“只要”。
My life seems to leave me like the sand flowing. I can hear that, but I can still smile only as long as I see you sleeping by my side.
我的生命正在慢慢地离开我，好象沙子从沙漏中流走一样，我听到了那流逝的声音，但只要你还熟睡在我身旁，我就依然笑得出来。
supposing(suppose)：假如。
Supposing his plan goes wrong, what will you do then?
provided；providing：只要。
I’ll dry the dishes, providing that you do the washing-up.
如果你刷盘子，我就将它们擦干。
in case：以防、防止。
In case memory is low, unused sessions are written out to permanent storage so they can be retrieved if the user comes back to the computer before the sessionexpires.
在内存不足的情况下，没有使用的会话就被写入持久存储中，这样当用户在会话到期之前回到计算机上时，可以检索到这些会话。
only if：只要；只要……就；只是在……的时候；只有。
This, of course, will happen only if you spend time to reflect on your life and work.
当然，这一切只是发生在你花时间来仔细思考你的生活跟工作之后。
2. 引导原因状语从句的连词有：
as：因为。
He is afraid of speaking in front of the class as he is shy.
他害怕在班上讲话，因为他害羞。
because：因为（通常回答why）。
I did it because they asked me to do it!
我做这事是因为他们请我做啊！
since：既然。
We have to resign ourselves to fate since we cannot think out an effective remedy.
既然我们想不出一个有效的挽救办法，我们只好听天由命了。
for：因为。
He must be at home for there is light in his room.
他肯定在家，因为他家有灯。
in that：在于（后面接原因）。
Karzai is a good person in that he brings peace, and brings a lot of clinics in the villages and hospitals to the city.
因为卡尔扎伊带来了和平，在许多村庄开设诊所，并在城市中修建了许多医院，他是个好人。
now that：既然；因为。
Now that you put your hand to the work, you should do your utmost to finish it.
既然你已经着手这项工作了， 那就应该尽力完成它。