Question

I think _____ is very important for students to study by themselves in the school or at home

1. A.
   it
2. B.
   this
3. C.
   that

Answer 1

A
考查代词it 做的是形式主语，真正的主语是后面的不定式。此题中I think后是一个宾语从句，it做主语，真正的主语为to study by themselves in the school or at home，句意：我认为对学生们来说在学校或在家里靠自己学习是非常重要的。故选A。