Prepositions are words that indicate spatial or temporal relationships between other words in a phrase. There are many types of prepositions including prepositions of place like "on", "at", "in", and prepositions of time like "since", "for", "ago". The preposition "since" is used with a particular point in time and usually with the perfect tense, while "for" is used with a period of time and can be used with any tense. Examples are given to demonstrate the correct usage of "since" and "for" in phrases involving time.

1. -Since
-ForPREPOSITIONS

2. PREPOSITIONS
What are they?
Words that combine with a noun or a pronoun to form a
phrase that usually acts as an adverb, adjective, or a noun.
(The “phrase” is referred to as the prepositional phrase.)
For example:
The cat is sitting on a tree.

3. PREPOSITIONS
In essence, prepositions talk about a relationship in space,
time, etc.
Prepositions of Place
On At In
Over Under Above
Below Across
Prepositions of Time
On At In
Since For Ago
Before To
Others
From Of By
On About Off

4. PREPOSITIONS
Examples:
We go to the park.
The test is on Monday.
Did you look under the table?
Picture of a bird.
I’m in the train.
The teachers will be back by tomorrow.
I would’ve walked around the house.
The laws were valid before 2009.
My dog likes to jump over the fence.
Let’s meet during lunch.
Get off the bus.

5. PREPOSITIONS
Prepositions of Time:
Since For
-Used when a particular
moment in time is involved.
-Used when a time period
is involved.

6. PREPOSITIONS
How and when to use for:
-For is used with a period of time.
-For can be used with all tenses.
The general form:
for + period of time

7. PREPOSITIONS
Examples:
I will sleep for 30 minutes.
The kids play for an hour.
I wanted to stay for a while.
She should have practiced for decades.
The WiFi has been malfunctioning for weeks.
They are leaving for several months.
for + a period of time

8. PREPOSITIONS
How and when to use since:
-Since is used with a particular point in time.
-Since is used when we talk about the past.
(Usually only used with perfect tense.) The general form:
since + point in time

9. PREPOSITIONS
Examples:
I have been working since 8 a.m.
She has lived in Delhi since 1990.
The AC hasn’t been functioning since a month ago.
Her parents have been calling since yesterday.
since + a point in time

10. PREPOSITIONS
Incorrect Usage:
They have been in town for a day. (Correct)
They have been in town since a day. (Incorrect)
She has been here for Monday. (Incorrect)
She has been here since Monday. (Correct)

11. PREPOSITIONS
Prepositions of Time:
Since For
-Used when a particular
moment in time is involved.
-Used when a time period
is involved.

12. PREPOSITIONS
End of Lesson