it won't be bong before.不久就.
It won't be long before they arrive here.
他们不久就会到达这里
不用till那有关till的是什么句子就是这老师也让找conj.直到…时(为止)Please wait for me till I come back.请等我回来。I sat up till she came back.我一直坐到她回来。I waited till they should return.我一直等到他们回来。He will wait till I arrive.他将等到我来。He had hardly reached the station till the train arrived.他刚到火车站, 火车就进站了。