eg：I will write to you the moment/minute I arrived in Paris.
(3)特殊单词：by the time that, every/each time(使用时后面不要再加when)
(4)till&until：
① 肯定形式表示的意思是"做某事直至某时"，动词必须是延续性的;
否定形式表达的意思是"直至某时才做某事"，一般用until，动词为延续性或非延续性都可以;
eg: I slept until midnight.
Wait till I call you.
She didn't arrive until 6 o'clock.
② Until可用于句首，而till通常不用于句首，通常用于句中;
eg: Until you told me, I had heard nothing of what happened.
eg：As you sleep you pass through a sequence of sleep states—light sleep, deep sleep and REM (rapid eye movement) sleep—that repeats approximately every 90 minutes.
