The glass door 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
网友回答
A. to let
(答案→)B. letting
C. let
D. having let
解析：句意：在入口处玻璃门代替了木门，这样在白天很容易让光进来。这里表目的时用不定式时表目的时前不能用逗号，但是这里可以用分词表示结果状语。故选B。