Peter is a brilliant language leaner. Within two weeks he has developed a good of Chines

问题补充：

Peter is a brilliant language leaner. Within two weeks, he has developed a good of Chinese and Japanese.

A. commitment

B. description

C. transformation

D. command

答案：

A. commitment

B. description

C. transformation

(答案→)D. command

解析：考察名词辨析。Commitment 承诺，保证 description 描述 transformation 转换，变形 command 命令，控制，指挥

A good command of sth 意为对……很精通