preposition, adverb, verb · it is for someone to do something; expresses agency or responsibility

今天的晚餐由我负责。

preposition, noun, verb · due to; because of

这场事故是由疏忽造成的。

preposition · starting from; via; through

游行队伍由天安门出发。

verb · to follow; to allow someone to have their way

凡事不能全由着他。