题干
——I want to put up the picture on the wall. Would you mind helping me with it?
—— ______. With pleasure.
A：Of course
B：Of course not
C：You'd better not
D：Thanks a lot
答案(点此获取答案解析）
B
变成 
，是 
的公差
≠0，
．若
是
与
的等比中项，则