Prepositions: At, To, On, For, Since

Rule
A preposition is followed by a "noun". It is never followed by a verb.
By "noun" we include:

• noun (dog, money, love)
• proper noun (name) (Bangkok, Mary)
• pronoun (you, him, us)
• noun group (my first job)
• gerund (swimming)

A preposition cannot be followed by a verb. If we want to follow a preposition by a verb, we must use the "-ing" form which is really a gerund or verb in noun form.
Quick Quiz: In the following sentences, why is "to" followed by a verb? That should be impossible, according to the above rule:

• I would like to go now.
• She used to smoke.

Here are some examples:

Subject + verb	preposition	"noun"
The food is	on	the table.
She lives	in	Japan.
Tara is looking	for	you.
The letter is	under	your blue book.
Pascal is used	to	English people.
She isn't used	to	working.
I ate	before	coming.

Answer to Quick Quiz: In these sentences, "to" is not a preposition. It is part of the infinitive ("to go", "to smoke").

Is it any wonder that prepositions create such troubles for students for whom English is a second language? We say we are at the hospital to visit a friend who is in the hospital. We lie in bed but on the couch. We watch a film at the theater but on television. For native speakers, these little words present little difficulty, but try to learn another language, any other language, and you will quickly discover that prepositions are troublesome wherever you live and learn. This page contains some interesting (sometimes troublesome) prepositions with brief usage notes. To address all the potential difficulties with prepositions in idiomatic usage would require volumes, and the only way English language learners can begin to master the intricacies of preposition usage is through practice and paying close attention to speech and the written word. Keeping a good dictionary close at hand (to hand?) is an important first step.

Prepositions of Time: at, in, on

We use:

• at for a PRECISE TIME
• in for MONTHS, YEARS, CENTURIES and LONG PERIODS
• on for DAYS and DATES

at	in	on
PRECISE TIME	MONTHS, YEARS, CENTURIES and LONG PERIODS	DAYS and DATES
at 3 o'clock	in May	on Sunday
at 10.30am	in summer	on Tuesdays
at noon	in the summer	on 6 March
at dinnertime	in 1990	on 25 Dec. 2010
at bedtime	in the 1990s	on Christmas Day
at sunrise	in the next century	on Independence Day
at sunset	in the Ice Age	on my birthday
at the moment	in the past/future	on New Year's Eve

Prepositions of Time: at, on, and in
We use at to designate specific times.
The train is due at 12:15 p.m.

We use on to designate days and dates.
My brother is coming on Monday.
We're having a party on the Fourth of July.

We use in for nonspecific times during a day, a month, a season, or a year.
She likes to jog in the morning.
It's too cold in winter to run outside.
He started the job in 1971.
He's going to quit in August.

Prepositions of Place: at, on, and in

Prepositions of Place: at, in, on

In general, we use:

• at for a POINT
• in for an ENCLOSED SPACE
• on for a SURFACE

at	in	on
POINT	ENCLOSED SPACE	SURFACE
at the corner	in the garden	on the wall
at the bus stop	in London	on the ceiling
at the door	in France	on the door
at the top of the page	in a box	on the cover
at the end of the road	in my pocket	on the floor
at the entrance	in my wallet	on the carpet
at the crossroads	in a building	on the menu
at the front desk	in a car	on a page

We use at for specific addresses.
Grammar English lives at 55 Boretz Road in Durham.

We use on to designate names of streets, avenues, etc.
Her house is on Boretz Road.

And we use in for the names of land-areas (towns, counties, states, countries, and continents).
She lives in Durham.
Durham is in Windham County.
Windham County is in Connecticut.

Prepositions of Location: in, at, and on and No Preposition
IN (the) bed* the bedroom the car (the) class* the library* school*	AT class* home the library* the office school* work	ON the bed* the ceiling the floor the horse the plane the train	NO PREPOSITION downstairs downtown inside outside upstairs uptown
* You may sometimes use different prepositions for these locations.

Prepositions of Movement: to
and No Preposition

We use to in order to express movement toward a place.
They were driving to work together.
She's going to the dentist's office this morning.

Toward and towards are also helpful prepositions to express movement. These are simply variant spellings of the same word; use whichever sounds better to you.
We're moving toward the light.
This is a big step towards the project's completion.

With the words home, downtown, uptown, inside, outside, downstairs, upstairs, we use no preposition.
Grandma went upstairs
Grandpa went home.
They both went outside.

Prepositions of Time: for and since

We use for when we measure time (seconds, minutes, hours, days, months, years).
He held his breath for seven minutes.
She's lived there for seven years.
The British and Irish have been quarreling for seven centuries.

We use since with a specific date or time.
He's worked here since 1970.
She's been sitting in the waiting room since two-thirty. 

Infomartion gathered from www.englishclub.com


For more help: http://www.englisch-hilfen.de/en/grammar/preposition_time.htm