心尖位于左侧第五肋间隙，距锁骨中线1—2厘米处。
参考答案：对
The traffic is heavy right now. I _____ arrive a bit late, so could you save me a place? [ ]
A. can
B. must
C. need
D. might
热力管网关断阀应安装在()。
A.干线的起点
B.干线的末端
C.支干线的起点
D.支干线的末端
E.热力入户井
