焊接接头内部缺陷有（）。 A.气孔 B.裂纹 C.未焊透 D.夹渣

—Why didn't you leave school? It's already eight o'clock.

—Because I _______ my homework yet. [ ]

A. wasn't finishing

B. wouldn't finish

C. haven't finished

D. wasn't finished

KerleyA线主要分布于()

A．上肺外周

B．下肺内侧

C．上肺内侧

D．中肺野

E．下肺外周

发生伤亡事故以后，当事人或事故现场的有关人员应当首先（）

A.抢救受伤人员

B.保护事故现场

C.抢救生产设备、物资

楚庄王作为春秋五霸之一，产生了许多成语典故，请试举出两个？

被告应是哪一个行政机关