YOU SAID:

last night was a lot of fun

INTO JAPANESE

最後の夜はとても楽しい

BACK INTO ENGLISH

Last night was so much fun.

INTO JAPANESE

最後の夜はとても楽しいでした。

BACK INTO ENGLISH

It was so much fun last night.

INTO JAPANESE

それはとても楽しいを最後の夜だった。

BACK INTO ENGLISH

It was so much fun last night.