A preposition shows the location or position of an object or person. The preposition is always the first word of a prepositional phrase.
Put your coat in the closet. The preposition is the word in.
The cat climbed over my shoes. The preposition is the word over.
The smoke drifted up the chimney. The preposition is the word up.
When a preposition is not used as part of a phrase, it becomes an adverb.
Look what happens when we use the prepositions in, over, and up without making them part of a phrase.
It’s cold outside, so you should come in.
I’m glad the school day is over.
The doorbell rang, so I jumped up.
Notice that these three words – in, over, up – can be used as prepositions when they are at the start of a phrase. However, when these words are used alone, they are no longer propositions. They are now adverbs describing how something is done.
A word can only be a preposition if the word is at the beginning of a prepositional phrase.
▶It’s your turn. Decide if this sentence has a preposition or an adverb. The squirrel scampered up the tree. Did you find the prepositional phrase? Good for you!