The Grammar Guide: Ending a Sentence with a Preposition.

Today, I'm going to go over whether or not you should end a sentence with a preposition. There are many different opinions on this topic. Technically, you should never end a sentence with a preposition. This is the grammar rule. However, many people agree that there are some cases in which an exception can be made. These people are of the opinion that it is okay as long as it isn't an "unnecessary preposition". So, here's your explanation!

A preposition is generally defined as a word that pertains to time or space.

They create relationships between other words. 

eg of temporal prepositions: before, since, after, following

eg of spatial prepositions: under, over, beside, by 

Now, an unnecessary preposition is one that does not change the meaning of the sentence. 

eg: I will go later on.

The "on" in "I will go later on." is completely useless, therefore, it should not be used. 

However, in some cases it makes more sense to use the preposition. 

eg: What was the book under?

In this case, most people would say that it is okay to end with the preposition. The alternative would be to write "Under what was the book?". While this is grammatically correct, no one speaks that way. 

For the most part, as long as you can justify your reasoning, any professor is going to be lenient on this sort of thing. Still, it may not hurt to ask what their standpoint is on the subject before turning in a big paper. Like I've said, TECHNICALLY you are never supposed to end with a preposition. However, most people (including those in the English community) agree that there can be an exception. 

Comment any questions!