电影票“9排21号”若记作(9,21),则(21,7)表示______.
9排21号”记作(9,21),则(21,7)表示21排7号.
故答案为:21排7号.
—Shall the salesman deliver the goods for you?
—No, I'd rather he __________. [ ]
A. hasn't delivered
B. has delivered them
C. hadn't delivered them
D. had them delivered
锅炉运行时,从炉膛热烟气到受热面金属外壁,热量传递方式是()。
A、对流
B、导热
C、辐射
D、既有对流又有辐射