1、现在完成时ThePresentPerfectTense含义“已经做过…”表示过去开始,但持续到现在的动作,或过去发生的动作,对现在留下后果或影响。二.结构1.肯定:have/has+p.p.(过去分词)2.否定:have/has+not+p.p.(过去分词)3.一般疑问:Have/Has提到句首Yes,…have/has.No,…haven't/hasn’t.三.标志词already,yet,before(以前),ever,never, just(刚刚),for+时间段(持续…)since+时间点(自从…)so far/up to now(到目前为止)already和yet的
2、区别already常用于肯定句中或句末;yet常用于一般疑问句或否定句末。e.g.1.Tom hasalreadyfinished his work.2.Tom hasn’t finished his workyet.for和since的运用for“经历(时间段)”since“自从…以来”for+时间段since+时间段+agosince+时间点since+从句1.He has stayed herefor 3 hours.2.He has stayed heresince 3 hours ago.3.He has stayed heresince 3 o’clock.
3、4.He has taught Englishsince he came here.动词的过去分词形式1.规则动词2.不规则动词finish--finished--finishedlive--lived--livedcarry--carried--carriedstop—stopped--stoppedEg.go—went—gonesee---saw—seenforget—forgot--forgotten区分短暂性动词与持续性动词.表示短暂性(瞬间性)的动词在现在完成时的句中不能和一段时间连用.即for,since短语或howlong问句(否定句除外)Ihavelived