"Be disappointed at" 是一个英语短语，用来表达对某人或某事的期望没有得到满足时的失望情绪。当你对某人或某事的期望没有达到预期，你可能会感到失望。这个短语可以用于描述对个人行为、结果、事件或情况的失望感。

**用法**

1. **结构**："Be disappointed at" 后面通常跟名词或动名词短语，表示引起失望的事物或人。

   - 例如：I am disappointed at your lateness.（我对你的迟到感到失望。）

2. **程度**：这个短语可以表达不同程度的失望，从轻微的不满到深深的沮丧。

   - 例如：She was slightly disappointed at the movie's ending.（她对电影的结局有点失望。）

   - 例如：He was deeply disappointed at the lack of progress in the project.（他对项目缺乏进展深感失望。）

3. **情感色彩**：这个短语带有负面情绪，但并不总是责备或生气，更多的是表达一种失落或沮丧的感觉。

   - 例如：Parents can be disappointed at their children's poor grades, but still love and support them.（父母可能对孩子差的成绩感到失望，但他们仍然会爱和支持他们。）

**例句**

1. I was disappointed at the restaurant's service; it wasn't up to my expectations.（我对这家餐厅的服务感到失望，它没有达到我的期望。）

2. She was disappointed at the news that her favorite band had canceled the concert.（听到她最喜欢的乐队取消了演唱会的消息，她感到失望。）

3. He was bitterly disappointed at his own performance in the competition.（他对自己在比赛中的表现深感失望。）

4. The company's shareholders were disappointed at the low profits reported in the annual report.（公司的股东们对年报中报告的低利润感到失望。）

5. The students were disappointed at not getting accepted into their dream university.（学生们因为没有被梦想的大学录取而感到失望。）

**同义词辨析**

1. **Be let down by**：与 "be disappointed at" 类似，表示因某人或某事未达到预期而感到失望。例如：I felt let down by my friend who didn't show up for our meeting.（我觉得朋友没来参加我们的约会让我失望。）

2. **Be disillusioned with**：强调原本的信仰、理想或期望破灭后的失望。例如：After years of working hard, he became disillusioned with the corporate world.（经过多年的努力工作，他对商界感到幻灭。）

3. **Be frustrated with**：更侧重于因无法实现目标或遭遇阻碍而产生的挫败感。例如：She was frustrated with her inability to solve the complex problem.（她对自己的无法解决复杂问题感到沮丧。）

4. **Be saddened by**：表示因悲惨或不愉快的情况而感到伤心。例如：The whole community was saddened by the loss of the beloved teacher.（整个社区都为失去这位受人尊敬的老师而感到伤心。）