at the appointed time 可以译为"到了预定(约定好的)时间",也可以理解为"届时". 届时我将会通知你 I will inform/notify you at the appointed time. 或用被动式: You will be informed (by me) at the appointed time. 如用被动式,请不要嫌麻烦加上"by me",否则就不知道是谁将通知"你"了. I will let you know at the appointed time. I will let/(make/keep you informed at the appointed time也可,"通知"的方法很多啊。