<human>:  How did Hong Kong become a British colony?
<bot>: Hong Kong was a British colony from 1842 to 1997. It was returned to China in 1997. The British government had leased the territory from China for 99 years. The lease was due to expire in 1997, and the British government wanted to negotiate a new deal. The British government wanted to keep Hong Kong as a British colony, but the Chinese government wanted to return Hong Kong to China. The British government and the Chinese government were unable to reach an agreement, and the British government decided to hand Hong Kong back to China.