時間狀語從句，條件句中，從句用一般現在時代替將來時

　　When, while, before, after, till, once, as soon as, so long as, by the time, if, in case , unless, even if, whether, the moment, the minute, the day, the year, immediately

　　He is going to visit her aunt the day he arrives in Beijing. 他一到北京，就去看他姨媽。

　　典型例題

　　表示現在已安排好的未來事項，行程等活動。

　　The museum opens at ten tomorrow.　博物館明天10點開門。