The boy likes to play tricks ____ girls, and his parents should cure him ______ that bad habit.

A．at; of

B．on; for

C．on; of

D．with; for

社区建设的基本原则首要的一条是（）。

A、以人为本，服务居民

B、扩大民主，居民自治

C、因地制宜，循序渐进