let-down

例句：

1. 1. I was disappointed when the movie didn't start on time.
   电影迟到了，我感到很失望。
2. 2.She let down her guard and fell for his lies.
   她放松了警惕，被他的话欺骗了。
3. 3. The team's performance let down their fans.
   球队的表现让球迷感到失望。