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1、Unit 3 Back to the pastGrammarPresent perfect tensePresent perfect tense Go over the news story on Page 2 and find the sentences using the present perfect tense. Please explain why the tense is used in these sentences. The disappearance of Justin (make)Kelly very unhappy. has made We use the present

2、 perfect tense to talk about things that happened in the recent past, but are connected to the present.THE USES OF THE PRESENT PERFECT TENSE I (not see)Justin since last Friday night. have not seenWe also use the present perfect tense to talk about something that started in the past, and is still ha

3、ppening now.COMPLETE THE FOLLOWING SENTENCES WITH THE PROPER TENSE. 1 We (study) English for about five years. 2 They (live) in the south since their daughter was born. 3 I (read) your article three times. Its well written. 4 The student (finish) her homework already. 5 Eric (go) back to his hometow

4、n today. 6 The police (just finish) searching the area.have studiedhave livedhave readhas finishedhas gonehave just finished We use the present perfect tense when the exact time of an action is not clear or important. We use it with time expressions such as: already ever for just lately never recent

5、ly since yet ALREADY,YET;FOR,SINCE We use already for affirmative statements and yet for negative statements. We use for + a period of time and since + a point in time. He has just gone out.(=He went out a few minutes ago.) We use the present perfect tense here to tell others that he isnt here now.

6、I have just heard the news.(Now I know the news.)We use the present perfect tense to talk about actions that were completed only a short time ago. In this case, just is used. Pay attention to the position of just. We can also use the present perfect tense for repeated actions, that is, we use the pr

7、esent perfect tense with the time expressions once/twice/three times T o m h a s r u n g u p t h r e e t i m e s t h i s morning.(Now it is still in the morning.) Tom rang up three times this morning.(Now it is not still in the morning.) Actions occurring in an incomplete period might be indicated b

8、y today or this morning /afternoon/evening/week/month/year/century or all day/night/week, all the time, always etc. Look at the following sentences and point out what tense or tenses are used in them and the reasons why they are used. 1 We have studied English for about five years. We began to study

9、 it five years ago . 2 They moved to the south in 1990 and have lived there since then. 3 Eric left home last year and has just come back. 4 Justin has been away from home for several days. He disappeared last Friday. 5 They bought this house three years ago and they have lived here since then. 6 My

10、 brother went to see my grandpa last week. He has visited him three times this month.THE PRESENT PERFECT TENSE AND THE PAST SIMPLE TENSE 1 you my pen? Yes, I it on your desk just now.(see) 2 you dinner? Yes, I it with Mary.(have) 3 the postman yet this morning? Did the postman come this morning?(com

11、e) 5 I him for a long time. Hello! I (not)you were here in Nanjing. How long have you been here?(know) Have seensawHave hadhadHave comehave knowndidnt know The present perfect tense is normally used for an action which lasts throughout an incomplete period, but with the past simple tense, we use tim

12、e expressions which a fixed point in the past. c.f. We havent seen Justin for a week.(He is still missing.) Justin disappeared last week.(It may mean that this week Justin is here.) He has smoked since he left school.(He still smokes.) He smoked for six months.(It means that he stopped smoking then.

13、 Sometimes, however, the action finishes at the time of speaking. It has been very cold lately but its just beginning to get warmer. On meeting someone, you may say: I havent seen you for ages.(But I see you now.) For a past action whose time is not definite and often has a result in the present.1 T

14、om has had a bad car crash.(Hes probably still in hospital now.) Tom had a bad car crash.(But hes probably out of hospital now.)2 The lift has broken down.(We have to use the stairs.) The lift broke down.( But its probably working again now.) Read the diary entry and then complete it using the corre

15、ct forms of the verbs in brackets. (2) saw (3) has visited (4) loves (5) hasnt visited (6) has swum (7) has never met (8) has dived (9) has found (10) hasnt found (11) Has, been Present perfect continuous tense THE USES OF THE PRESENT PERFECT CONTINUOUS TENSE 1 I for an hour and he still hasnt turne

16、d up.(wait) 2 I m s o s o r r y I m l a t e . y o u long? We sometimes use the Present perfect continuous tense to talk about actions that started in the past and are still continuing, or have just finished but are still connected to the present in some way.have been waitingHave been waiting Go over

17、 Points 1 and 2 on page 9.THE FORM OF THE PRESENT PERFECT CONTINUOUS TENSE We form the present perfect continuous tense with have/has been and the present participle of the verb. Answers: (2) have been talking (3) have been taking (4) have been watching (5) have seen (6) have been writing Present pe

18、rfect or present perfect continuous tense? Li Jia has read a book about Stonehenge. Li Jia has been reading a book about Stonehenge. In the first sentence, it means the action read isnt still continuing, and Li Jia knows what the book is about now, but in the second sentence , it means the action re

19、ad is still continuing. c.f. Ive cleaned the house. Ive been cleaning the house. Read Point 1 on page 10. I Egypt twice this month.(visit) I Egypt for two months. (tour) The present perfect continuous tense cant be used with time expressions such as twice or how many times, because in this tense the

20、 action is continuous, not stopped and started again. We can use the present perfect tense for repeated actions, and the present perfect continuous tense for non-stop actions.have visited have been touringHOW MANY TIMES/HOW LONG have you swum in the lake? have you been swimming in the lake? We usual

21、ly use the present perfect tense to ask questions beginning with how many/much, and the present perfect continuous tense to ask questions beginning with how long.How many timesHow longA STATE VERB OR AN ACTION VERB I have had this camera for five years.(state verb) I have taken photos of UFOs with t

22、his camera.(action verb) I have been taking photos of UFOs with this camera.(action verb) An action means something happening or changing. A state means something staying the same. Some examples of action verbs are do, go, and play. Some examples of state verbs are like, know and exist. A state verb

23、 doesnt mean an action, so it cant be used in a continuous tense. Theyve always had a big garden. How long have you known each other? Hes been in hospital since his accident. Ive never visited Paris. Ive already been to Paris. always, never, yet, already and ever cant be used in a continuous tense.

24、I have not been sleeping well since I returned home. Ive been waiting for an hour. We can use for and since with the the present perfect continuous tense. Answers on page 11 A (1)heard (2) been doing (3) been researching (4) been doing (5) started (6) done (7) read (8) found (9) started (10) been do

25、ing (11) been making Sample answers B 1 He has been waiting at an underground station. 2 They have been traveling in an UFO. It looks like a saucer. 3 They probably have talked to animals or plants on the earth as well as creatures on other plants. 4 They have visited Mars, Venus, Jupiter and some o

26、ther planets. How long have you learnt English? Or How long have you been learning English? It has snowed for a long time. It has been snowing for a long time.BOTH PRESENT PERFECT TENSE AND PRESENT PERFECT CONTINUOUS TENSE An action which began in the past and is still continuing or has only just finished can, with certain verbs, be expressed by either the present perfect or present perfect continuous.Verbs which can be used in this way include expect, hope, learn, lie, live, sleep, sit, study, wait, want, rain, etc. Homework Part C1 and C2 on page 88 in Workbook Prepare Task