can not be closed

例句：

1. 1. I can't believe you left without telling me.
   我不敢相信你离开时没有告诉我。
2. 2. She cannot swim well in the cold water.
   她在冷水中游泳不好。
3. 3. He cannot understand the complex math problem.
   他不理解这个复杂的数学问题。