YOU SAID:

i had fun at the party last night

INTO JAPANESE

昨夜のパーティーで楽しかった

BACK INTO ENGLISH

It was fun at the party last night

INTO JAPANESE

昨夜のパーティーは楽しかった

BACK INTO ENGLISH

Last night's party was fun

INTO JAPANESE

昨夜のパーティーは楽しかった

BACK INTO ENGLISH

Last night's party was fun