The Australian boy has a good of Chinese and can communicate with others freely.A. reques

问题补充：

The Australian boy has a good of Chinese and can communicate with others freely.

A. request

B. command

C. demand

D. usage

答案：

A. request

(答案→)B. command

C. demand

D. usage

解析：考查名词和词组：A. Request要求，B. Command命令，掌握C. demand 要求，D. Usage使用，have a good command of是固定词组“精通”，句意：这个澳大利亚男孩精通汉语，可以和别人自由的交流。选B。