The Correct Use of Prepositions
Prepositions, simply expressed, are words that show the relationship between nouns. For example:
The book is on the table.
Here, the nouns, ‘book' and 'table', are shown to be related by use of the preposition, 'on'. Simple, isn’t it? There are, of course, more complex examples such as:
Under the tree, there was an old, wooden bench.
Ask yourself, here, which words are the nouns, then try to find out which word is showing their relationship to one another. The nouns are 'tree' and 'bench' and the word which shows how they fit together is 'under'; hence, 'under' is the preposition. Whenever you are trying to locate a preposition, find the nouns first, then follow the process outlined above, asking yourself which word is connecting the nouns, this will be the preposition. A few of the more common prepositions are: under, over, above, on, below and beneath - but there are many more.
It is, in fact, precisely because the preposition is showing a connection that it is considered bad grammar to end a sentence with a preposition. To clarify, here is an example of a sentence which ends with a preposition and is therefore grammatically incorrect:
He did not have a shelf to put the book on.
This sounds awkward because the nouns' relationship is not explained until the end of the sentence. The correct grammatical usage of the preposition in this sentence is:
He did not have a shelf on which to put the book.
You can see that in the correct version, the preposition connects the nouns more naturally. In good Standard English, you should try to avoid using a preposition at the end of a sentence but it is sometimes unavoidable. There is a famous example of Winston Churchill, who was very particular about grammar, stating jokingly: ‘That is the kind of language up with which, I will not put!' So, even the most fastidious grammarians make allowances and this rule should be applied with a degree of flexibility governed by common sense.