Below are some examples of sentences from classic literature using words classed as Prepositions.
Prepositions include words such as:
after, as, before, by, down, for, from, in, on, over, to, under, up, with.
Prepositions join a Noun, Pronoun or Noun Phrase to the rest of the sentence. For example:
• Would he have to go into court as a witness? [Preposition + Noun Phrase]
A Noun, Pronoun or Noun Phrase can be made the subject of a Verb, making a complete stand-alone sentence. For example:
• could be vital.
[e.g. ‘A witness’, ‘It’, ‘The testimony of an honest man’]
If what follows your word already has a Verb, and so could stand by itself as a sentence, then your word is unlikely to be a Preposition.
• “Then spare my life, as I spared yours.” [Conjunction + Clause]
In this case, the Pronoun ‘I’ has a verb of its own (‘spared’) already, so ‘I spared yours’ isn’t a Noun Phrase, but a Clause. Consequently, ‘as’ is a Conjunction, not a Preposition.