I felt it an honor to speak here.A. to askB. to be askedC. askingD. having asked

问题补充：

I felt it an honor to speak here.

A. to ask

B. to be asked

C. asking

D. having asked

答案：

A. to ask

(答案→)B. to be asked

C. asking

D. having asked

解析：根据题意，被邀请到这演讲，我深感荣幸。我是被邀请对象，故用被动语态，选B。