为沿胸骨边缘与前正中线平行的垂直线（）
A.前正中线
B.胸骨线
C.锁骨中线
D.肩胛线
E.后正中线
参考答案：B
Edward, you play so well. But I _____ you played the piano. [ ]
A. didn't know
B. hadn't known
C. don't know
D. haven't known
克服沟通障碍的有效途径包括( )。
A．利用反馈
B．精简语言
C．主动倾听
D．情绪控制
E．制定编码
