_____ many times, but he still couldn't understand it. [ ]

A. Though he had been told

B. Having been told

C. Having told

D. He had been told

异位ACTH综合征较常见的水电解质及酸碱平衡紊乱是()

A.稀释性低钠血症伴代谢性碱中毒 

B.低血钾性碱中毒 

C.高血钾性碱中毒 

D.低血钾性酸中毒 

E.高血钠性碱中毒