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.