Prepositions link their objects to the other structures within the sentence. They are used to show placement, time, direction, cause, and location. They can be used alone or in two-or three-word combinations. Unfortunately, prepositions are often used idiomatically and often contradict rules. Therefore, their use must be memorized. There are, however, a few rules that will help you.

Pattern to remember

At is used for a specific time.

Incorrect: We will convene to 10:00 A.M.

Correct: We will convene at 10:00 A.M.

On is used for a specific day.

Incorrect: The deadline is at Friday

Correct: The deadline is on Friday

In is used for a specific city.

Incorrect: She was born at San Francisco.

Correct: She was born in San Francisco.

On is used for specific date.

Incorrect: The contract was signed in September 5.

Correct: The contract was signed on September 5.

By: Arif