China is developingof all the countries in the world.A. fastB. fasterC. fastestD. the most

问题补充：

China is developingof all the countries in the world.

A. fast

B. faster

C. fastest

D. the most fast

答案：

A. fast

B. faster

(答案→)C. fastest

D. the most fast

解析：句意：在世界上中国是所有国家中发展最快的国家。后面有of all the countries所以用最高级，fast的最高级直接加est,所以选C。