The reasons Hong Kong has no choice are simple: their economic reliance on the mainland is deep, the people have no political strength to resist, and it lacks the support of international allies.
理由非常簡單﹘﹘一是香港的經濟依賴中共非常深；二是香港人民沒有政治力量來抵抗中共的壓力；三是香港根本沒有國際友邦的支持。