Prepositional phrases have a variety of functions. They can modify a noun, as in "the child with a runny nose," or verbs, as in "she came from Panama." When PPs modify verbs, they have functions that can often be filled by adverb phrases, or occasionally by other phrase types as well. Constituents that function in this role are sometimes called adverbials, because these constituents answer adverb-like questions such as when, where, how, or why. Similarly, PPs that modify nouns are sometimes called adjectivals. But be careful with these terms. They do not imply that the PPs actually become adverbs or adjectives. Remember that adjective and adverb are categories for words, not for phrases. The terms adverbial and adjectival simply tell you what sort of constituent the phrase modifies. Because this information can also be conveyed by a tree diagram, we won't use these particular terms much, but you should be aware of them, since other works on English grammar use them frequently. We will have more to say about the various roles that PPs fill after we have finished our survey of phrase types.