缺乏幽默感

例句：

1. 1. He often finds himself at a loss for words when discussing complex issues.
   当他讨论复杂问题时，他常常找不到合适的词汇。
2. 2. The teacher noticed that the students were lacking in their ability to express themselves clearly.
   老师注意到学生们在清晰地表达自己方面有所欠缺。
3. 3. The lack of humor in the presentation made it difficult for the audience to connect with the speaker.
   演讲中缺乏幽默使得听众难以与演讲者产生共鸣。