dumbness

例句：

1. 1. The child was so dumb that he couldn't understand the instructions.
   这个孩子太笨了，听不懂指示。
2. 2. He was too dumb to realize that his mistake could cost him his job.
   他太笨了，没有意识到他的失误可能会失去工作。
3. 3. She felt a sense of dumbness when she realized how much she had missed out on.
   当她意识到错过了那么多时，她感到了一种无能为力的感觉。