一道关于非谓语的

问题描述:

一道关于非谓语的
The glass doors have taken the place of the wooden ones at the entrance,_____ in the natural light during the day.
A.to let B.letting C.let D.having let为什么答案是b ,不能选a ,做目的状语?

好像是现在分词作伴随状语,表状态.我知道了,如果选a的话就变成玻璃门想要了