現(xiàn)在完成時(shí)（結(jié)構(gòu)：have+過去分詞）
(1) 現(xiàn)在完成時(shí)表示從過去持續(xù)到現(xiàn)在的動(dòng)作或狀態(tài) 現(xiàn)在完成時(shí)的這種用法通常與由since或for引導(dǎo)的時(shí)間狀語連用.如：The old man have lived here for more than twenty years.老人已在此住了20多年了.(2) 現(xiàn)在完成時(shí)表示過去發(fā)生的對(duì)現(xiàn)在有影響的動(dòng)作 [1] 現(xiàn)在完成時(shí)的這種用法有時(shí)不帶時(shí)間狀語,有時(shí)可以和already,before,ever,just,lately,never,once,recently,yet等一些所指時(shí)間不具體的時(shí)間狀語連用.如：Have you ever been to Australia?你去過澳大利亞嗎?[2] 有時(shí)現(xiàn)在完成時(shí)和now,today,this morning,this week,this year等表示現(xiàn)在的時(shí)間狀語連用.如：I haven' t seen him today.我今天沒見過他.I have seen him only once this year.我今年只見過他一次.(3) 現(xiàn)在完成時(shí)在時(shí)間和條件狀語從句中表示將來完成的動(dòng)作 I'll go to the party as soon as (or when) I have finished my homework.我完成作業(yè)后就去參加聚會(huì).(4) 現(xiàn)在完成時(shí)和until now,so far,in the past few years,up to the present等表示從某時(shí)到目前這段時(shí)間的狀語連用 I have not heard from her so far.到目前為止,我沒有收到過她的信.We have learned five hundred words up to the present.到目前為止,我們已學(xué)了五百個(gè)生詞.但要注意：當(dāng)意義明確時(shí),適用現(xiàn)在完成時(shí)的句子可以不用時(shí)間狀語.如：He has done a lot of work.他干了許多工作.She has told me about her story.她跟我講過她的故事.