我是否有必要花那么多钱开这个聚会。（wonder）

I wonder whether it is necessary for me to spend so much money in holding the party.

i wonder if i should spend so many money on this party

I wonder whether it is necessary to spend so much money on holding the party.

楼上的句子很好.把in 改成on就好了.spend 的介词搭配是on/for