it was ______ that he could not finish it by himselfa so difficult a workb such a difficult work为什么不选a

问题描述:

it was ______ that he could not finish it by himself
a so difficult a work
b such a difficult work
为什么不选a

SUCH来形容名词
来形容形容词

so difficult a work 中
difficult a work是名词,so只能形容 形容词,所以用形容名词的such.