I will not go to the gathering unless officially _________-.

问题描述:

I will not go to the gathering unless officially _________-.
A.invited
B.to be invited
C.inviting
D.invite
为什么不能选B?

invited
被动
句意:我不会去聚会除非被正式得邀请.
officially 是副词 修饰动词.
这里应该是省略了 i was (officially invited)