The US government, concerned about protecting its interests in China and maintaining open trade, issued the Open Door notes, which proposed the idea of sharing trading rights in China among all nations. This highlighted the US's desire to be a major player in post-Boxer Rebellion China and established its presence on the global stage. rephrase like a 8th grader
The US government was worried about keeping its business in China safe and making sure trade stayed open. So, they came up with the Open Door notes, which suggested that all countries should get to share the right to trade in China. This showed that the US wanted to be important in China after the Boxer Rebellion and show off its power to the world.
