肯定句：
I slept until midnight. 我一直睡到半夜时醒了。
Wait till I call you. 等着我叫你。
（在肯定句中可用before代替 Let's get in the wheat before the sun sets.）
否定句：
She didn't arrive until 6 o'clock.
她直到6点才到。
Don't get off the bus until it has stopped.
公共汽车停稳后再下车。
I didn't manage to do it until you had explained how. 直到你教我后，我才会做。
1)Until可用于句首，而till通常不用于句首。
Until you told me, I had heard nothing of what happened.
直到你告诉我以前，出了什么事我一点也不知道。
2)Until when 疑问句中，until要放在句首。
---Until when are you staying? 你呆到什么时候？
--- Until next Monday. 呆到下周一。
注意：否定句可用另外两种句式表示。
(1）Not until …在句首，主句用倒装。
Not until the early years of the 19th century did man know what heat is.
直到19 世纪初，人类才知道热能是什么。
Not until I began to work did I realize how much time I had wasted.
直到我开始工作，我才认识到了我已蹉跎了几多岁月。
(2) It is not until… that…
