如何区分exercise,exercises,practice,activities,activity?

如何区分exercise,exercises,practice,activities,activity? 如何区分financing activities和investing activities exercise&exercises activity什么时候变activities activities和exercises的区别 Exercise和exercises什么区别? 关于exercise,exercises的用法 exercise和exercises的区别? exercise和exercises的用法 what activities与what activity区别 financing activities 和operating activities怎么区分 exercise和practice的区别