1、1Unit 1 Past and present单元语法专练现在完成时(一)1.定义:表示从过去持续到现在的动作或状态,或已完成但对现在有一定影响的动作。常和 already,ever,just,never,recently,yet等副词及 since,for引导的时间状语从句连用。2.结构:have/has+动词的过去分词。(1)肯定句:主语+have/has+动词的过去分词+其他。(2)否定句:主语+have/has+not+动词的过去分词+其他。(3)一般疑问句:Have/Has+主语+动词的过去分词+其他?(4)特殊疑问句:特殊疑问词或词组+一般疑问句(have/has+主语+过去分词
2、+其他)?3.动词的过去分词的变化规则。(1)规则动词。规则动词的过去分词的构成规则与规则动词的过去式的构成规则相同。主要有以下四种变化规则:一般动词,在词尾直接加 ed。例如:workworkedworked,visitvisitedvisited以 e结尾的动词,只在词尾加 d。例如:livelivedlived,carecaredcared以“辅音字母+y”结尾的动词,将 y变为 i,再加 ed。例如:studystudiedstudied,crycriedcried重读闭音节结尾,末尾只有一个辅音字母,先双写该辅音字母,再加 ed。例如:stopstoppedstopped,dropd
3、roppeddropped(2)不规则动词。2AAA 型。例如:costcostcost,cutcutcut,hithithitAAB 型。例如:beatbeatbeatenABA 型。例如:becomebecamebecome,runranrunABB 型。例如:bringbroughtbrought,buyboughtboughtABC 型。例如:beginbeganbegun,givegavegiven4.用法。(1)表示过去发生的某一动作对现在造成的影响或结果。这是现在完成时的基本用法。例如:Haveyouevertravelledonaplane?你曾经坐飞机旅游过吗?Ivejust
4、finishedreadingthebook.我刚读完那本书。(2)表示过去已经开始,持续到现在的动作或状态。这是现在完成时的另一种用法,可以和表示从过去某一时刻延续到现在(包括“现在”在内)的一段时间的状语连用。例如:WhathaveyoudonesinceyoujoinedGreenerChina?自从加入“绿色中国”组织后,你做了什么?Howlonghaveyoubeenatthisschool?你在这所学校待多久了?.根据句意用所给词的适当形式填空1.They have finished (finish) their homework by now. 2.How long has Mr
5、 Smith taught (teach) English so far? 33.John has played (play) this computer games a few times. 4.I have repaired (repair) over ten bicycles since last Monday. .根据汉语意思完成句子,每空一词1.你曾经去过香港吗?Have you ever been to Hong Kong? 2.我们已经几年没有见到雪了。We havent seen snow for a few years. 3.他从昨天晚上开始就感觉不舒服。He hasnt f
6、elt well since last night . 4.你最近收到家人的来信了吗?Have you heard from your family lately/recently ? .单项填空(B)1.I in this area over the years.I here five years ago. A.lived;have movedB.have lived;movedC.lived;movedD.have lived;have moved(B)2.Have you seen the film ? Never.A.ago B.before C.after D.later(C)3.Have you given the book back to the library ? Yes,I have given it back. A.yet;yet B.already;alreadyC.yet;already D.already;yet(D)4.Have you spoken to an Englishman?4No.Ive met a foreigner.A.never;ever B.never;yetC.ever;ever D.ever;never
