初中一道英语选择题关于so和such的

It is _____ easy work that we can finish it in a short time.
A.so B.such C.so an D.such an
老师说选择B.请问为什么,我知道单数时怎么区分,可work是不可数,这个时候,我不会区分用法了,请问怎么区分,谢谢
答：B
译：这是这么容易的工作,我们都能在很短的时间内完成.
分析：1. so+adj. /adv. that. 如此地.,以致于.
2. such+n. that. 这样的.,以致于.
so是副词,跟形容词或另一个副词.
Such是限定词,后跟名词.
要注意的是句型2,因为:
一、这个名词有三种形式1)不可数名词,2）可数名词单数, 3）可数名词复数.
二、这个名词前常有形容词.请不要将它与句型一混淆了!
这三种情况分别举例对比一下：
1. He made such rapid progress that the teacher praised him.
2. He is such a good teacher that we all like him.
3. They are such good teachers that we all like them.
做1,3两题句时,眼光要看远一些,不要只见good,不见后面的名词!
还要注意句子2,我们还可以通过交换 a与good的位置,将such改成so:
He is so good a teacher that we all like him.
注意其不同的翻译：such a good teacher 这样的一个好老师
so good a teacher 如此好的一个老师
还要注意的是,如果名词前的“形容词”many, much, few, little（其实应叫限定词,因为它们与good, beautiful这样的形容词其实不在同一类）时,用so,不用such:
so many falls that...
so few books that...
so much work that...
so little water that.
又要注意little的两重性.上面四个词是指“多,少”的意思.little还可以作真正的形容词,修饰名词,表示“小的”,这时该用such还是要用such的：
I was surprised that such little children could finish so much work within so little time.