_____________ the ability to speak, so he used sign language to communicate with others.

A．As he lost

B．He lost

C．Having lost

D．His being lost

嗜铬细胞瘤所致高血压，首选的降压药是（）

A.血管紧张素转化酶抑制剂

B.血管紧张素Ⅱ受体拮抗剂

C.酚妥拉明

D.利尿药

E.钙通道阻断药