The foundation of English rests on the hundreds of words that have a definite role to play in communication. A verb and a noun are essential parts of sentences, which form the basic unit of communication. Adverbs and prepositions are parts of speech that play a specific role in English. We have seen how adjectives modify nouns. An adverb modifies a verb and it communicates much more meaning than just a verb. A preposition is a word that is used before a noun and it helps describe a relationship between other words in a sentence. A noun or a verb by themselves have some meaning and carry more meaning when used in a sentence. Similarly adverbs and prepositions by themselves do not mean much but they can be exceptional when used in sentences. Phrasal verbs are expressions that comprise a combination of a verb and either a preposition or an adverb. Phrasal verbs provide different meanings to the original verb they are formed from.