左冠状动脉（）
A.起自升主动脉起始部
B.分前室间支和旋支
C.只分布于左心室和左心房
D.营养右心房
E.有分支至室间隔前2/3部
参考答案：B, E
All her attention is ____ on her children and she seems to have little time for anything else. [ ]
A. guided
B. aimed
C. directed
D. concentrated
( )是期货交易中最常见、最需要重视的一种风险。
A．市场风险 B．信用风险 C．流动性风险 D．操作风险
