2. A drop of water wears away the stone, but a rope saw breaks the wood.
3. The story of Bian Que meeting Cai Huangong
4. The subprime mortgage crisis in the United States started as a little bubble every year and eventually evolved into a global financial crisis, which has to make people think that "disasters often accumulate in small amounts".
5. A levee of a thousand miles is broken by an ant nest.