as soon as 和until的区别?

you must have lunch as soon as possible.
你必须马上吃中饭.
you must finish your homework until I come back.
在我回来前你必须完成你的作业.
as as表示“当……的时候”,往往和when/ while通用,但它着重强调主句与从句的动作或事情同时或几乎同时发生.She came up as I was cooking.(同时)
until表示这件事发生还有个过程,再此过程到某某时候这时间段内