尽早预订以避免失望。

Book early to avoid ___disappointment.

令我非常失望的是，他决定离开。

To my great ___disappointment, he decided to leave.

然而，令我失望的是，餐厅因为正在装修而关闭。

However, to my ___disappointment, the restaurant was closed because it was being redecorated.