It was + 時間段+before….“過了多久才(怎么樣)……”
　　It was not long before….“不久，就……”
　　It will (not) be +時間段+before….“要過多久(不久)……才……”(before從句謂語動詞要用一般時態)
　　[例句]
　　It was not long before he sensed the danger of the position.不久他就意識到他處境的危險。
　　It was five days before he came back. 五天后他才回來。
　　It will be half a year before you graduate from the school. 再過半年你才能畢業。
　　It will not be long before they understand each other. 他們大概不久就會互相了解。