English Grammar Review
Prepositions and Conjunctions

Preposition Necessity

To communicate effectively, we often write our words in the same way that people speak their words. Unfortunately, this is not always the best advice for the use of prepositions.

Miguel and I will research a couple things.
[common speech]

Miguel and I will research a couple of things.
[correct]

In your writing at work, play it safe and include the preposition. They are essential to proper use of English grammar. Few readers will even notice when you purposely write correctly.

Sometimes being correct in this way can sound stuffy. Even if this is so, play it safe and include the proper preposition when you are writing at work.

What use is this effort in Mexico City?
[common speech]

Of what use is this effort in Mexico City?
[correct]

Also, when you use the phrase all X but X is a pronoun, you should add the preposition of to form all of X.

All the staff members agreed.
[okay]

All of them agreed.
[correct]

A more subtle problem involves prepositions in parallel. Try to include all the proper prepositions.

Margarita has a strong interest, as well as a high regard for, maintainable code.
[common speech]

Margarita has a strong interest in, as well as a high regard for, maintainable code.
[correct]

Note: When every element of a series uses the same preposition, repetition is not needed.

He made a burrito with beans, rice, and guacamole.
[clear]

He made a burrito with beans, with rice, and with guacamole.
[awkward]

Exceptions

(1) The main exception to always including the proper preposition: when it adds nothing to the meaning of the sentence.

Where is he at?
[okay]

Where is he?
[equivalent, so acceptable]

More examples:

It's near to your desk.
[okay]

It's near your desk.
[acceptable]

He fell off of the desk.
[okay]

He fell off the desk.
[acceptable]

Her desk is opposite to yours.
[okay]

Her desk is opposite yours.
[acceptable]

(2) It is considered acceptable to not include the preposition of in certain expressions, such as what color eyes and what size car.

Lesson: Preposition Necessity
Module: Prepositions and Conjunctions
Course: English Grammar Review