Preposition Tips: How to Use For and On

A common mistake we see while proofreading is incorrect use of prepositions. Although short, these words are vital for creating grammatical sentences. As such, we’re looking at two you may see every day: “for” and “on.”

What Are Prepositions?

Prepositions are words that specify a relationship between a noun and another word in a sentence. For example:

Kate is going to the class.

In this sentence, the preposition “to” tells us where Kate is going by linking the verb “going” with the noun “class.” The trouble is that many prepositions have various uses, which can make picking the right word difficult.

But if you can remember some of the main uses of “for” and “on,” you’ll find it much easier to express your intentions clearly.

Preposition #1: For

“For” has many different uses, including:

• Indicating who should to have something (e.g., I have good news for you!)
• A reason or cause (e.g., I couldn’t see the horizon for the fog.)
• Illustrating a span of time or distance (e.g., The road is straight for miles.)
• Meaning “On the occasion of” (e.g., She got a new car for her birthday.)
• Expressing support or agreement (e.g., I voted for change!)
• Comparing something against expectations (e.g., It’s big for a sandwich!)
• Showing something is done to help someone (e.g., I’ll I carry that for you.)
• Being a representative of a group (e.g., She works for the company.)
• Exchanges (e.g., I swapped my hat for a tiara.)

This isn’t a definitive list! But it does cover some common uses. And if you practice using this term in different contexts, you master it.

Preposition #2: On

The preposition “on” has several uses, too. It can mean the following:

• Covering or being in contact with a surface (e.g., You have ink on your shirt.)
• Something will occur at a specific time (e.g., The game is on Friday.)
• Being positioned above or atop something (e.g., The lizard sat on the rock.)
• Using something, often a machine (e.g., He’s always on the phone!)
• Something is dependent on something (e.g., She’s on life support.)
• Immediately after (e.g., On realizing their mistake, they took action.)
• About or concerning (e.g., I wrote my thesis on lexical ambiguity.)
• Via a medium, particularly electronic media (e.g., I saw it on TV.)
• The state of something (e.g., The roof is on fire!)
• Direction or location (e.g., Stop when you see the fire station on your left.)
• Paid for or supported by (e.g., Students often live on a limited budget.)

As above, this list isn’t complete since “on” is a very flexible word. That why it’s good to practice using prepositions until you’re familiar with their meanings! Having someone check your work for misplaced prepositions is a good idea, too, as you can learn from their feedback.