________ he read about the subject, ________ interested he becam

________ he read about the subject, ________ interested he became.
A、So. . . that
B、So. . . as
C、As. . . as
D、The more. . . the more
【正确答案】：D
【题目解析】：the more..., the more....越....越....
句意：他对这个问题了解得越多，就越感兴趣。