
Prepositions
Prepositions are not as scary as they appear! They are mostly logical in that they follow some basic principles and most have a complementary preposition with an opposite meaning. So, sit back and relax as we introduce you to these principles.
Prepositions: Locators in Time and Place
A preposition describes a relationship between other words in a sentence, locating something in time and space, modifying a noun, or telling when or where or under what conditions something happened.
Prepositions that describe location
The most common use of prepositions is in describing the location of an object, person or place in relation to another object, person or place.
For example: The World Trade Center is on Av. Nações Unidas, next to the River Pinheiros and one block from Av. Berrini.
Most prepositions that relate to location obey two basic principles: they relate to a surface or they relate to a volume. For example, a table is considered a two dimensional surface:

The instructor is UNDER the table.
But a bathtub is considered a three dimensional volume with an inside and an outside.

The man is IN the bathtub.


The man is BESIDE the counter. The receptionist is BEHIND the counter.

The fish is ON the plate. The penguin is ON a piece of ice, which is floating ON the water. The sun is BEHIND the penguin because it is casting a shadow IN FRONT of him. Some icebergs are BEYOND the penguin in the distance.


The laptop is IN the waste bin. The secretary is INSIDE an office building. She is putting a pen INTO her mouth.
AT
At is the main exception to the rule of surface and volume. It is nearly always used to describe the exact location of time or place.
For example: Where are you, now?
I’m at the airport. I’m at the doctor’s surgery.
I’m at the crossroads of Av. Kubitschek and Faria Lima.
Or: We are having a meeting at 7 o’clock.
Giving location of addresses:
We use at for specific addresses.
For example: Valerie Smith lives at 55 Boretz Road in Durham.
We use on to designate names of streets, avenues, etc.
For example: Her house is on Boretz Road.
And we use in for the names of land-areas (towns, counties, states, countries, and continents).
For example: She lives in Durham. Durham is in Windham County. Windham County is in Connecticut.
Words like home, downtown, uptown, inside, outside, downstairs, upstairs, describe a location.
For example: Grandma went upstairs. She and Grandpa later went outside.

Kirsty went UPSTAIRS to bed...eventually.

Prepositions that describe direction of movement
To and From
We use to when expressing the destination of an action.
For example: They were driving to work together.
She's going to the dentist's office this morning.
Toward (or towards) is a variant spelling of the same word - use whichever sounds better to you.
For example: We have taken some steps towards our objective.
From is the opposite of ‘to’ and describes the origin or starting point.
For example: This message is from your wife.
My grandparents came from Italy.

The boy presented the flowers TO his teacher. The flowers were FROM all the children in her class.

Any word with the suffix ‘ward’ describes the direction of movement.
For example: The car slid backwards down the hill.
Inflation has continued its upward trend.

The pair walked UP the ramp WITH the sofa and INTO the truck.
Through always describes a movement or location in which something has two parts outside and one part inside.

The arrow is THROUGH the apple.
Examples: The train passed through a tunnel.
The child looked through the window and saw a cat outside.

The child fell THROUGH the ice.
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Prepositions of Time
We use at to designate specific times.
For example: The train is due at 12:15 pm.
We use on to designate days and dates.
For example: 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.
For example: 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.
For and Since
We use for when we measure time (seconds, minutes, hours, days, months, years).
For example: 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.
For example: He's worked here since 1970.
She's been sitting in the waiting room since two-thirty.
During
During is used for events that occurred or existed throughout the duration of a specific period of time.
For example:
Our young baby sleeps a lot during the day.
During the Great Recession, interest rates stayed very low.
By, Before and Until
By, before and until can all be used to indicate deadlines or to mark a specific point in time.
For example:
If we have a ‘deadline’ of February:
We must complete the project by February.
We must complete the project before February.
We have until February to complete the project.
For example:
When we wish to fix a sentence at a particular time or point in the past:
Before 1950, few people in Britain had flown in an airplane.
By 1970, many people had flown in an airplane.
Until the introduction of commercial airlines, few people experienced flying.
