The use of since and For

1. Present Perfect
Since and For

2. Who Is Bill Gates?
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.

3. Form 1
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 Microsoft’s programs.

4. Form 2
Form 2
Past participles can be regular or irregular.
irregular
The regular form of the past participle is
base form of verb + -d or -ed.
Gates has always loved
working with computers.

5. Form 3
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.

6. Form 4
Form 4
Note these common irregular past participles.
participles
write – written
give
– given
be – been
see – seen
read –
read do

7. Present Perfect
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

8. Using Since 1
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

9. Using Since 2
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

10. Change the sentences to present
Practice 1 perfect. Add the since phrase in
parentheses and delete any past
tense time phrases.
Example: Maria was in the garden yesterday. (since 9 a.m.)
Maria has been in the garden since 9 a.m.
1. Bill Gates wrote many many emails since(since 1975)
Bill Gates has written emails yesterday. 1975.
2. They gave a lot of books books to schools since 1990.
They have given a lot of to schools last year. (since 1990)
3. II saw many friends last weekend.came home. home)
have seen many friends since I (since I came
4. My sister read read many articles night. last August.
My sister has many articles last since (since last August)
My friend has worked at a pizza place since 2003.
5. My friend worked at a pizza place a year ago. (since 2003)

11. Using For
Using For
Use for + length of time to show how long
something has lasted.
Millions of people have used Gates’s
software for three decades.
for the last the last three decades.
now
for three decades
past future
have used Gates’s software

12. Since and For
Since and For
Note the difference between since and for .
since + point in for + length of
time time
five o’clock ten minutes
yesterday two days
last summer three decades
1996 many years
he was a child a long time

13. Complete the sentences with
Practice 2 since or for.
Example:
Bill Gates has been married to Melinda
since
French Gates ___________ 1994.
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 hasn’t given me any problems __________
last year.