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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 substantial
  amount of money to organizations working in
  global health.

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Form 1
The present perfect is formed with

form of have
past participle
Bill Gates has been the CEO since 1975.
Many people have used Microsofts programs.
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Form 2
Past participles can be regular or irregular.
The regular form of the past participle is base
form of verb -d or -ed.
Gates has always loved working with computers.
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Form 3
Past participles can be regular or irregular.
There are many irregular past participles.
Gates has been the CEO since 1975.
He and his wife have given lots of money to
schools.
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Form 4
Note these common irregular past participles.
write written give given
be been see seen
read read do done
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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).
Bill Gates has been CEO of Microsoft since 1975.
since 1975.
now
past
future
has been CEO
1975
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Using Since 1
Use the present perfect with since point in
time to show when something started.
Bill Gates has written several books since 1975.
since 1975.
now
past
future
has written several books
1975
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Using Since 2
Since can also introduce a time clause.
time clause
Gates has programmed computers since he was 13
years old.
since he was 13 years old.
now
past
future
has programmed computers
age 13
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Change the sentences to present perfect. Add the
since phrase in parentheses and delete any past
tense time phrases.
Practice 1
Maria was in the garden yesterday. (since 9
a.m.)
Example
Maria has been in the garden since 9 a.m.
1. Bill Gates wrote many e-mails yesterday.
(since 1975)
Bill Gates has written many e-mails since 1975.
2. They gave a lot of books to schools last year.
(since 1990)
They have given a lot of books to schools since
1990.
3. I saw many friends last weekend. (since I came
home)
I have seen many friends since I came home.
4. My sister read many articles last night.
(since last August)
My sister has read many articles since last
August.
5. My friend worked at a pizza place a year ago.
(since 2003)
My friend has worked at a pizza place since 2003.
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Using For
Use for length of time to show how long
something has lasted.
Millions of people have used Gatess software
for the last three decades.
for the last three decades.
now
for three decades
future
past
have used Gatess software
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Since and For
Note the difference between since and for .
since point in time
for length of time
five oclock yesterday last summer 1996 he was a
child
ten minutes two days three decades many years a
long time
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Practice 2
Complete the sentences with since or for.
Example
Bill Gates has been married to Melinda French
Gates ___________ 1994.
since
for
1. Computers have been used in schools __________
more than a decade.
since
2. I have had a computer in my office __________
the mid-1990s.
for
3. Many students have worked with computers
__________ many years.
since
4. My computer hasnt given me any problems
__________ last year.