Mobile phones are very popular in China now and they are than before.A. more cheapB. much

问题补充：

Mobile phones are very popular in China now and they are than before.

A. more cheap

B. much cheaper

C. the cheapest

D. quite cheaper

答案：

A. more cheap

(答案→)B. much cheaper

C. the cheapest

D. quite cheaper

解析：比较级用于表示两个事物间进行对比，最高级用于三个及三个以上事物进行对比。单音节 形容词副词的比较级是在后面加er，much可修饰形容词比较级，表示程度， quite一般不用于修饰比较级，可以修饰最高级。故选B。