I was disappointed to find that they had left already.
我发现他们已经离开了，觉得很失望。
He was disappointed to see she wasn't at the party.
看到她没来参加晚会，他感到很失望。
I'm disappointed in you ─ I really thought I could trust you!
你真让我失望——我原以为可以相信你的.！
I was disappointed by the quality of the wine.
这酒的质量令我失望。
Don't raise your hopes too high, or you may be disappointed.
不要希望过高，否则你可能会失望的。