根据下面一段对话内容，从7个选项中选出能填入空白处的最佳选项，其中有两项为多余选项。
A:Excuse me. ()
B:Yes. You don’t know me,of course.I don’t teach here.I just give oral examinations here now and then. Don’t be nervous.
A:Nervous Who Me
A．You must have wronged me.
B．Oh! I’m so sorry about this.
C．Please stop just a second.
D．Are you Mr. Smith
E．But may I ask you something first
F．Is there anything I can do for you
G．Now, sit down please.