dumb as an oyster

例句：

1. 1. He was so dumb that hecouldn't even understand the question.
   他太愚蠢了，以至于无法理解这个问题。
2. 2.The child was too dumb to speak properly.
   那个孩子太笨了，不会说话。
3. 3. She was dumbfounded by the unexpected news.
   她对这突如其来的消息感到震惊。