YOU SAID:

i had butterflies in my stomach when i saw jim in the gym.

INTO JAPANESE

ジムでジムを見たとき、お腹に蝶がいた。

BACK INTO ENGLISH

When I saw the gym at the gym, I had a butterfly on my stomach.

INTO JAPANESE

体育館で体育館を見たとき、お腹に蝶がいた。

BACK INTO ENGLISH

When I saw the gymnasium at the gymnasium, there was a butterfly on my stomach.

INTO JAPANESE

体育館で体育館を見たとき、お腹に蝶がいた。

BACK INTO ENGLISH

When I saw the gymnasium at the gymnasium, there was a butterfly on my stomach.