英語六級-聽力口語關鍵句67.直到我走進辦公室，我才意識到自己的錯誤.

67. I didn't realize my mistake until I entered the office.

點睛　

not...until句型使用廣泛，表示“（不）……直到”。其中，not可以省略。如：
Wait until tomorrow. 等到明天。

考點歸納　

與not...until句型類似的是till，二者用法的區(qū)別比較微妙，需要特別注意：
當主句是否定句時，意思是“直到（某時）（某動作）才（發(fā)生）”，這時候常會使用not until的結構；如果將not until結構放在句首，那么主句要用倒裝形式。如：
1) He didn't go to sleep until 12 last night. 他昨晚直到12點鐘才睡覺。
2) Not until we pointed out their fault to them did they realize it. 直到我們指出他們的錯誤，他們才意識到。
當主句是肯定句時，意思是“直到（某時某動作停止了）”，這時候常會使用till。如：
1) The students made much noise till the teacher came into the classroom. 直到老師走進教室，學生們才停止了吵鬧。
2) Don't open it till your birthday. 等到你生日那天再打開。
另外，until可以放在句首，而till則不行。如：
1) Until they used up all their money, the young couple were very happy. (√)
2) Till they used up all their money, the young couple were very happy. (×)