until 是直到.
如:You have to stand on it until you can go against it .
not until 是在...之前
如:You can not go against it until you can earn your life .
until一般不放在句首,后面跟时间词连用
如：He came back until midnight.
not until:可放句首,但主句要用倒装．
Not until midnight did he came back home.
还有一种用法与until相似．
He did not come back home until midnight.
until
prep.
(=to the time of)直到...时,到...为止
[常用在否定句中](=before)在...以前; 直到...才; 不到...(不)
until his death
直到他死
until four o'clock
直到四点钟
He did not go until night.
他直到夜里才走.
It was not until yesterday that I noticed it.
直到昨天我才注意到这件事.
两个不能说区别,因为not until本来就是until的否定,表示直到.才