损伤性气胸行闭式引流的常用位置为伤侧
A．锁骨中线第1肋间
B．锁骨中线第2肋间
C．锁骨中线第3肋间
D．腋中线第7肋间
E．腋中线第8肋间
参考答案：B
TCP (Transmission Control Protocol) was specifically designed to provide a reliable end-to-end byte stream over a(n)（）.
A．IP address
B．reliable network
C．socket
D．unreliable internet work
我国电网的额定频率是（）
A.30Hz
B.50Hz
C.80Hz
D.55Hz
