The correct answer is live.
The sentence should read: "I used to live in China."
This is because "used to" is followed by the base form of the verb (infinitive without "to").
اذا كان لديك إجابة افضل او هناك خطأ في الإجابة علي سؤال I used to ______ in China (1 lives live lived اترك تعليق فورآ.