椎管内阻滞麻醉最常见的并发症是（）。

A.呼吸困难

B.局麻药中毒

C.低血压

D.尿潴留

E.恶心呕吐

If only he _______ quietly as the doctor instructed, he would not suffer so much now.

A．lies

B．lay

C．had lain

D．should lie