Tom thought it was an honor to speak in the ceremony.
A. to invite
B. to be invited
C. inviting
D. having invited
网友回答
A. to invite
(答案→)B. to be invited
C. inviting
D. having invited
解析：考查it充当形式主语。It是形式主语，Tom和invite构成被动的关系。to be invited to speak in the ceremony是真正的主语。句意：Tom认为被邀请在庆典上发言是一件光荣的事情。