Prepositions can be tricky for English learners. There is no definite rule or formula for choosing a preposition. In the beginning stage of learning the language, you should try to identify a preposition when reading or listening in English and recognize its usage.

• to the office
• at the desk
• on the table
• in an hour
• about myself

A preposition is used to show direction, location, or time, or to introduce an object. 

Here are a few common prepositions and examples.

On

Used to express a surface of something:

• I put an egg on the kitchen table.
• The paper is on my desk.

Used to specify days and dates:

• The garbage truck comes on Wednesdays.
• I was born on the 14th day of June in 1988.

Used to indicate a device or machine, such as a phone or computer:

• He is on the phone right now.
• She has been on the computer since this morning.
• My favorite movie will be on TV tonight.

Used to indicate a part of the body:

• The stick hit me on my shoulder.
• He kissed me on my cheek.
• I wear a ring on my finger.

Used to indicate the state of something:

• Everything in this store is on sale.
• The building is on fire.

At

Used to point out specific time:

• I will meet you at 12 p.m.
• The bus will stop here at 5:45 p.m.

Used to indicate a place:

• There is a party at the club house.
• There were hundreds of people at the park.
• We saw a baseball game at the stadium.

Used to indicate an email address:

• Please email me at abc@defg.com.

Used to indicate an activity:

• He laughed at my acting.
• I am good at drawing a portrait.

In

Used for unspecific times during a day, month, season, year:

• She always reads newspapers in the morning.
• In the summer, we have a rainy season for three weeks.
• The new semester will start in March.

Used to indicate a location or place:

• She looked me directly in the eyes.
• I am currently staying in a hotel.
• My hometown is Los Angeles, which is in California.

Used to indicate a shape, color, or size:

• This painting is mostly in blue.
• The students stood in a circle.
• This jacket comes in four different sizes.

Used to express while doing something:

• In preparing for the final report, we revised the tone three times.
• A catch phrase needs to be impressive in marketing a product.

Used to indicate a belief, opinion, interest, or feeling:

• I believe in the next life.
• We are not interested in gambling.