tailieunhanh - Present Perfect- since and for

Bill Gates is one of the richest and most successful business executives in the world. Millions of people have used his computer programs for the past three decades. Bill Gates has always loved working with computers. In fact, he has programmed computers since his early teens. | Present Perfect: Since and For Bill Gates and Microsoft 6 Who Is Bill Gates? Bill Gates is one of the richest and most successful business executives in the world. Millions of people have used his computer programs for the past three decades. Bill Gates has always loved working with computers. In fact, he has programmed computers since his early teens. He has been the CEO of Microsoft Corporation since 1975. Since then, Bill Gates has written several books and has given billions of dollars to schools. For the last several years, he and his wife Melinda have donated a substanial amount of money to organizations working in global health. Form 1 The present perfect is formed with: Bill Gates has been the CEO since 1975. Many people have used Microsoft’s programs. + form of have past participle Form 2 Past participles can be regular or irregular. Gates has always loved working with computers. The regular form of the past participle is base form of verb + -d or -ed. Gates has been the CEO since 1975. He and his wife have given lots of money to schools. Form 3 There are many irregular past participles. Past participles can be regular or irregular. Form 4 Note these common irregular past participles. write – written give – given be – been see – seen read – read do – done Bill Gates has been CEO of Microsoft since 1975. Present Perfect Use the present perfect to talk about something that began in the past and continues into the present (and may continue into the future). future 1975 past now since 1975. has been CEO Bill Gates has written several books since 1975. Using Since 1 Use the present perfect with since + point in time to show when something started. future 1975 past now since 1975. has written several books Gates has programmed computers since he was 13 years old. Using Since 2 Since can also introduce a time clause. future age 13 past now since he was 13 years old. has programmed computers time clause Change the sentences to present perfect. Add the since phrase in parentheses and delete any past tense time phrases. Maria was in the garden yesterday. (since 9 .) Practice 1 Maria has been in the garden since 9 . 1. Bill Gates wrote many emails yesterday. (since 1975) 2. They gave a lot of books to schools last year. (since 1990) 3. I saw many friends last weekend. (since I came home) 4. My sister read many articles last night. (since last August) 5. My friend worked at a pizza place a year ago. (since 2003) Example: Bill Gates has written many emails since 1975. They have given a lot of books to schools since 1990. I have seen many friends since I came home. My sister has read many articles since last August. My friend has worked at a pizza place since 2003. Millions of people have used Gates’s software for the last three decades. Using For Use for + length of time to show how long something has lasted. future past now for the last three decades. have used Gates’s software for three decades Since and For Note the difference between since and for . five o’clock yesterday last summer 1996 he was a child since + point in time for + length of time ten minutes two days three decades many years a long time Complete the sentences with since or for. Bill Gates has been married to Melinda French Gates __ 1994. Practice 2 1. Computers have been used in schools _ more than a decade. 2. I have had a computer in my office _ the mid-1990s. 3. Many students have worked with computers _ many years. 4. My computer hasn’t given me any problems _ last year. Example: since for since for since References Copyright © 2006 Pearson Education and its licensors. All rights reserved.