YOU SAID:

she was at a party doing

INTO JAPANESE

彼女はパーティーで

BACK INTO ENGLISH

she is at a party

INTO JAPANESE

彼女はパーティーにいる

BACK INTO ENGLISH

she is at the party

INTO JAPANESE

彼女はパーティーにいます

BACK INTO ENGLISH

she is at a party

INTO JAPANESE

彼女はパーティーにいる

BACK INTO ENGLISH

she is at the party

INTO JAPANESE

彼女はパーティーにいます