 Phrases are intermediate constituents between sentences and words. Here is a sentence, The cat sat when the dog ran. This sentence consists of two clauses, the main clause, the cat sat, and the subordinate clause, when the dog ran. The main clause consists of two phrases, where the first, the cat, is composed of two words and the second sat just of one word. Phrases form single syntactic units, which can be moved around and substituted by another word or another phrase. In the cat sat on the mat, we have three phrases. So let's move them around. On the mat, the cat sat. Or let's replace phrases by some other elements, as in it sat there. All phrases have a head. It is the central and obligatory element which determines the type and the distributional properties of the phrase. The head can be preceded, followed, or surrounded by modifiers. Here are four variants of a noun phrase. One with a head only, fat. One with a pre-modifier, the hot fat. One with a post-modifier, fat on the mat. And one with both, the pre-modifier, the hot and the post-modifier on the mat. Further, major phrase types include adjectival phrases, such as quite happy with the result. Adverb phrases like quite independently of other people. Prepositional phrases such as straight into the pond. Or verb phrases like furiously kicked the ball. Note that phrases can be embedded within one another.