焊接时两接触面要求错误的是
A．紧密接触
B．可离开0.1～0.15mm
C．面状
D．表面粗糙清洁
E．点状
参考答案：E
My plane at 8:30 am, so I _______ home at 8:00 tomorrow morning.
A．leaves; leave
B．leaves; am leaving
C．is leaving; am leaving
D．is leaving; leave
石油燃料按其用途和使用范围可分为几种？
