It was + 时间段+before….“过了多久才(怎么样)……”

　　It was not long before….“不久，就……”

　　It will (not) be +时间段+before….“要过多久(不久)……才……”(before从句谓语动词要用一般时态)

　　[例句]

　　It was not long before he sensed the danger of the position.不久他就意识到他处境的危险。

　　It was five days before he came back. 五天后他才回来。

　　It will be half a year before you graduate from the school. 再过半年你才能毕业。

　　It will not be long before they understand each other. 他们大概不久就会互相了解。