加极上氧化铝的目的是（）、（）和（）。
参考答案：保温；防止阳极氧化；降低钢爪与炭块之间压降
A quality assurance team should be ______. ①associated with any particular development group ②depended upon any particular development group ③responsible for reporting directly to management ④in-depended upon any particular development group
A．①②
B．②③
C．③④
D．①②③④
TOSI锅炉在何处装有空气加热器？
