A.derivation
B.conversion
C.affixation
D.backformation
A.防止油品氧化、防止生锈
B.防止设备生锈以后,塔底泵和回流泵频繁堵塞影响开车进程
C.防止可燃性气体与空气形成爆炸性混合物在高温明火条下产生爆炸事件
D.防止精馏塔开车时,因为系统内空气的存在导致精馏塔超压
A.Consumer income rose, causing a supply shift.
B.Bad weather caused a supply shift.
C.Consumer income rose, causing a demand shift.
D.Supply and demand both shifte
E.None of the above are plausible descriptions.