____in bed is bad for your eyes

题目

____in bed is bad for your eyes
为什么是reading?固定词组吗?不能填read?

答案

其实动词作主语,要么加—ING,要么加TO.
所以就是reading而不是read.
同样,如果加TO,也相当于代替加ING的写法：
To read in bed is bad for your eyes.