A preposition is a word or group of words that gives information about where, when or how something takes place.

The boy was riding his bike beside the lake.

He always went for a bike ride after lunch.

Today he was alone but he usually went with his brother.

There are over a hundred prepositions in the English language. Here are a few of them:

at, during, on, with, under, over, by, in front of, behind, towards, among, before.