1)還可表示動作發(fā)生在過去，并且一直延續(xù)到現(xiàn)在，甚至還可能繼續(xù)延續(xù)下去。這時常和since所引導(dǎo)的短語或從句或for引導(dǎo)的短語連用(for有時可以省去)。
How long have you been in Beijing ? －I have been in Beijing for four years.你在北京呆了多久?--我在北京呆了四年。
Isaac's father has been a school teacher since 1968. 艾薩克的父親從一九六八年以來就當(dāng)教師。
We haven't had a vacation for a long time.我們好久沒放假了。
Three years have passed since we left school.我們畢業(yè)已經(jīng)三年了。
[注]但在下面的句子中，主句的謂語動詞可以用現(xiàn)在一般時。如：
It is three years since I began to work on the state farm.我在國營農(nóng)場工作已經(jīng)三年了。(美國英語用has been，下例同此)
It's a long time since I saw you last.好久沒見了。
2)在條件、時間狀語從句中表示將來完成的動作。
I'll go with you when I have finished my home work，我做完作業(yè)后就和你一塊去。
We'll wait here until you have Written the letter.我們將在這里等你寫完信。
Perhaps I'll know more English after I have learnt it for two years.我學(xué)完兩午后，懂的英語或許就會多些了。