—Are you free after school? —Sorry. I’ve planned to treat a friend of mine to dinner for h

问题补充：

—Are you free after school?

—Sorry. I’ve planned to treat a friend of mine to dinner for his help.

A. in addition

B. in turn

C. in return

D. in total

答案：

A. in addition

B. in turn

C. in return

D. in total

解析：介词短语辨析。Ａ另外；Ｂ依次，轮流；Ｃ作为回报；Ｄ总共，共计；句意：—放学以后你有空吗？—打不完。我计划去请一个朋友吃饭一回报他的帮助。根据句意什么吗Ｃ正确。