many times, but he still couldn't understand it.
A. Having been told
B. Though he had been told
C. He had been told
D. Having told
网友回答
A. Having been told
B. Though he had been told
(答案→)C. He had been told
D. Having told
解析： 句中的but是连词，要连接两个相同的结构，本题中连接两个分句。