一道英语中考题.要有解析.

问题描述:

一道英语中考题.要有解析.
-Are you going to the party {} at Smith's home?
-I will if I am free
A.holding B.held C.to hold D.to be held.

D.
翻译:你会去在史密斯家(将要举行的)聚会吗?如果我有空我就去.
the party后面需要被动语态作它的定语,排除A C.
动词将来时的被动语态作后置定语.to 表将来,held 的将来被动语态是to be held