兩者在用法上應注意以下幾點：
1.相關主句謂語必須是持續性動詞,若是終止性動詞,則應為否定式（因為終上性動詞一旦被否定就成為狀態,便可持續）.如：He waited until she was about to leave.他等著一直到她準備離開.She didn’t marry until she was over fifty.她直到50多歲才結婚.
2.引導時間狀語從句時,其謂語要用現在時表示將來意義.如：I won’t leave until he comes back tomorrow.我要等他明天回來后再走.Continue in this direction until you see a sign.一直朝著這個方向走就看見指示牌了.
3.有時其后可跟副詞或介詞短語等.如：He has been ill until recently.他最近一直生病.Until when are you going to stay here?你在這兒要待到什么時候?We didn’t eat till past midnight.直到午夜過后我們才吃飯.She won’t go home until after the exam.她要考完試之后再回家.如果語境的需要,有時甚至可以接帶有“引導詞”的從句.如：Don’t leave until after I’ve spoken to you.我和你說完后再離開.