____ many times ,but he still couldn't understand it.

问题描述:

____ many times ,but he still couldn't understand it.
A having been told B having told
C he had been told D though he had been told
答案是选择C,为什么呢?

C he had been told
他被告知好几次,但是还是不能理解
这里的关键在于but
连词but连接两个句子
所以前后都是需要谓语的完整句子,这句不是非谓语.