Prepositions are very important to the meaning of a sentence. A misused preposition can make a clearly stated sentence a confusing jumble of words. They are difficult to learn because of the sheer number of them in the English language and their capacity to have many meanings.
There are different types of prepositions. Time prepositions include before, after, during and until. Place prepositions include inside, on top and between. And direction prepositions include across, up and down.
Prepositions are considered ‘closed class’. In other words, they are a select group of words to which no new words are added. This is in contrast to nouns, adjectives and verbs.
Prepositions can vary from one language to another. For example, in Swedish something is considered ‘in the stairs’ rather than ‘on the stairs’. For a student learning English as a Second Language, this can make it challenging to shift the conventions of their native language to English.