I've been a teacher for five years.現(xiàn)在完成時.
I had been a teacher for five years till . 過去完成時.
如果你現(xiàn)在還是老師就用現(xiàn)在完成時.如果你以前作了5年老師,現(xiàn)在不是老師了就用過去完成時,并把截至?xí)r間寫在句子中“till” 后那這樣說對嗎i've ever been a teacher for five years. 可以表示曾經(jīng)當(dāng)了5年的老師嗎？這么說不對。ever表示曾經(jīng)做過，但是不能延續(xù)。別人可以問你Have you every been a teacher? 你也可以說I have ever been a teacher.但是不能說i've ever been a teacher for five years. 只能現(xiàn)在完成時或者過去完成時。說“已做過五年老師”強調(diào)的是時間持續(xù)，而ever強調(diào)“經(jīng)歷過”。