Prepositions are relationship words. They give clues and guidance regarding how the remainder of the sentence fits together. There are several important rules when using prepositions in the context of a sentence. These rules relate to how prepositions can be used, which prepositions can be used when, and where prepositions have to go in the sentence.
A preposition is a word that explains the time, space or logical relationship between the other parts of the sentence. In other words, it links all the other words together, so the reader can understand how the pieces of the sentence fit.
There are hundreds of prepositions in the English language. One easy way to remember prepositions is that they are words that tell you everywhere a bunny can run; for example, a bunny can run:
All of these words, and many more, are prepositions.
There are two major rules when it comes to the use of prepositions.
Determining the correct preposition to use can be a tricky proposition. This can be especially difficult when dealing with idioms - expressions in the English language that don't necessarily make sense when taken literally. Idiomatic expressions are expressions you just have to memorize, and when errors are made, they are almost always preposition errors.
Here are some examples of idioms, along with the correct prepositions:
Each of the italicized words are the only acceptable prepositions to follow these words. It would not be grammatically correct to say "able with" or "capable to"
Prepositions must always be followed by a noun or pronoun. That noun is called the object of the preposition. A verb can't be the object of a preposition.
This rule may seem confusing at first, because you may have seen words that look like verbs following the preposition to in sentences; for example:
However, in these examples, "ski" and "skiing" are not actually acting as verbs.
Because prepositions must be followed by a noun and have an object, they usually shouldn't be used at the end of a sentence. For example, it is not correct to say:
However, there are certain circumstances where it is acceptable to end a sentence with a preposition. These exceptions exist where the preposition is not extraneous. In other words, the preposition needs to be there, and if it wasn't, the meaning of the sentence would change.
In the above example, "The table is where I put my books on" the use of the preposition "on" isn't necessary. We could take the "on" out of the sentence and the meaning would be the same. So, the use of the preposition was extraneous or unnecessary and we don't need it.
However, here is an example where it is perfectly acceptable to use a preposition to end a sentence:
If you removed the "on" from the end of this sentence, it would change the meaning. Instead of switching on the set, you would be saying that you turned the TV itself.