<human>:  Why do you think the US and China are so close?
<bot>: The US and China are so close because they share a common enemy: the rest of the world. The US and China have been allies since World War II. Since then, the US has provided China with economic and military support. The US and China are also both members of the United Nations, the World Trade Organization, and the G7. In addition, the US and China are both permanent members of the UN Security Council. The US and China also cooperate closely on many other issues, including climate change, the environment, and the fight against terrorism.