But it is too hard__4___learn another language well.People must work very hard.

题目

But it is too hard__4___learn another language well.People must work very hard.
A.that B.as C.for D.to
选什么、为什么?

答案

选D
too...to..."太...,而不能,"
但是它是太难了而不能学好另一种语言.