仔细分析下列表格中烃的排列规律，判断排列在第15位烃的分子式是
A．C6H12
B．C6H14
C．C7H12
D．C7H14
答案：B
There is going to be a wonderful party _____ the evening of October lst, 2009. [ ]
A. in
B. on
C. at
D. for
当加工面与不加工面有同轴度要求时应选加工面为粗基准。( )
