The computer system____ suddenly while he was searching for information on the Internet.

A．broke down

B．broke out

C．broke up

D．broke in

由左、右冠状动脉同时供血的心室壁是（）

A.左心室前壁

B.左心室侧壁

C.左心室前间隔

D.左心室后壁

E.左心室心尖部