Answer:
Britain invaded the Chinese mainland and occupied the island of Hong Kong on January 25th, 1841, using it as a military staging point. China lost the war and had to cede Hong Kong to Britain in the Treaty of Nanking. As a result, Hong Kong became a crown colony of the British Empire.
Step-by-step explanation:
You can see this explanation at thoughtco dot com. I have just copied the text form there. I think this is the short, clear answer.
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