现在完成时的否定疑问句，表强调GT: Hasn't Mary told you? She invited Charlotte and me to dinner this evening.
I said I would be at your house at six o'clock,but the boss wants me to do some extra work.“是否” I'll have to stay at the office. I don't know when I'll finish. 一般疑问句变宾语从句， 宾语从句 用 if 引导宾语从句 Oh, and by the way,
= arrive at your house 加班
顺便问一句
陈述语序
my wife wants to know if Mary needs any help.