Many young people just can’t live without the Internet,         they depend on for whatever information they need.

A．which

B．when

C．where

D．what

洋地黄类药物禁用于下列哪种情况下的急性左心衰竭（）

A.急性心肌炎

B.重度二尖瓣狭窄伴快速心室率的房颤

C.肥厚型心肌病

D.甲亢性心脏病

E.肺源性心脏病