The document discusses the use of the present perfect tense in English. It provides examples of sentences using the present perfect to talk about actions that happened at an unspecified time before now or that started in the past and continue in the present. It also explains how the present perfect is used with "since" to specify a starting point in the past or "for" to indicate a duration of time.

1. How have
You been?

2. Function
We use the Present Perfect to say that an action
happened at an unspecified time before now.
The exact time is not important.

3. She has seen that movie twenty times.
I think I have met him once before.
People have not traveled to Mars.
Have you read the book yet?
Examples

4. Form
I have been to France twice.
Ruby has never broken a leg.
Have you ever eaten sushi?

5. Function
We often use since and for to say
how long the action has lasted.
 specifies the starting point (“since”)
 specifies the amount of time (“for”)
To talk about an action which started in the
past and continues up to now

6. I have had a cold for two weeks.
She has been in England for six months.
Mary has loved chocolate since she was a little girl.
Examples

7. I have been a teacher for more than ten years.
We haven’t seen Louis since Friday.
Form

8. ‘since’
 We use 'since' to specify the starting point
in the past
“I've known Sam since 1992.”
“I haven’t spoken with her since last Monday.”
“She's been here since 2 p.m.”

9. ‘for’
 We use 'for' with a period of time
(minutes, hours, weeks, months, years)
“She’s known Sam for 10 years.”
“We’ve been here for 3 hours.”
“I’ve had this cold for a week now.”