下面哪些属于DBBP530物理结构()
A.WMPT单板
B.UTRP单板
C.BBP/BBI单板
D.UPEU单板
参考答案:A, B, C, D
In the informal meeting the exporter learned that the importer was interested purchase rather than prepacked sets of 12.
A.in bulk
B.in essence
C.at random
D.at ease
简述内弯矩形角钢圈制作。