<human>:  Why did the Mongols invade China?
<bot>: The Mongols invaded China because they wanted to expand their empire. The Mongols had a large army and they wanted to conquer as much land as possible. The Mongols were also trying to find a place to settle down and become a permanent part of China. The Mongols were not able to find a good place to settle down in China so they decided to attack China.