usually和always是介词吗

usually和always是介词吗 usually和always的区别 always和usually有什么区别RT usually/always/often可以替换使用吗? always、usually后面都要加S吗? 像usually always 这样的频率复词后接动词原形吗,如果是第三人称呢? usually和often和always有什么不同啊 什么时候用never,seldom,sometimes,ofthe,usually和always usually是不是介词 always,often,usually用法 usually often sometimes always 是分为哪一类的? often的同义词是什么?是usually还是always? 在can always usually 后面还能用动词复数吗 for和to是介词吗 介词是甚么说明介词短语和介词 always often usually 等词能与一般过去时连用吗?always often usually 等词能与一般过去时连用吗?例如：I always played basketball with my friends. nerver seldom often usually always usuai、usually、always的区别