YOU SAID:

Last night, I ate dinner at a restaurant with my brother and sister.

INTO JAPANESE

最後の夜、私は弟と妹と一緒にレストランで夕食を食べた。

BACK INTO ENGLISH

Last night, I ate dinner at the restaurant with his brother and sister.

INTO JAPANESE

最後の夜、私は弟と妹とレストランで夕食を食べました。

BACK INTO ENGLISH

Last night, I had dinner with my brother and sister and a restaurant.

INTO JAPANESE

最後の夜、私は私の弟と妹とレストランで夕食を食べた。