YOU SAID:

Does he have a contract? We don't know.

INTO JAPANESE

彼は契約を結んでいますか？わかりません。

BACK INTO ENGLISH

Is he signed a contract? I do not know.

INTO JAPANESE

彼は契約書に署名していますか？私は知らない。

BACK INTO ENGLISH

Has he signed the contract? I do not know.

INTO JAPANESE

彼は契約書に署名しましたか？私は知らない。

BACK INTO ENGLISH

Did he sign the contract? I do not know.

INTO JAPANESE

彼は契約書に署名しましたか？私は知らない。

BACK INTO ENGLISH

Did he sign the contract? I do not know.