party（除非party是政党的意思,但题目已经指明是派对）  举例： Here  is  a  rough  guide  to  show  you  how  many  varieties  of  food  and  drink  you  will  need  at  the  party, 这里有个指南,告诉你如何为派对准备多种食品和饮料. On  the  party,the  host  announced  their  engagement. 在派对上,主持人宣布了他们订婚的消息. John  and  Mary  first  met  each  other  on  a  friend’s  birthday  party. 约翰和玛丽最初在朋友的生日派对上认识. 或者大致上这么说吧,谈论到人,用on  the  party,谈论到事情,at  the  party.On  the  party其实用得颇多,但具体使用时仍须看语境和具体要说什么.
"在派对上"翻译成英语是"at the party"还是"in the party",还是两者都可?