butas are
但as是
butas can
但as可以
butas will
但as将
butas did
但as做了
butas have
但as有
butas had
但as曾有
butas must
但as必须
butas may
但as可能
butas need
但as需要
butas might
butas are
但as是
butas can
但as可以
butas will
但as将
butas did
但as做了
butas have
但as有
butas had
但as曾有
butas must
但as必须
butas may
但as可能
butas need
但as需要
butas might
探索常用高频词汇