病院の予約は何時？って英語でなんて言うの？

ご質問ありがとうございます。

「病院の予約は何時？」の場合は①の"What time is the hospital appointment?"又は、"What time is the appointment at the hospital?"と言えます。

「何時に病院の予約をした？」は②の"At what time did you make the appointment with the hospital?"、又は"For what time did you make the appointment with the hospital?"

ご参考に。