Sentences are built from parts ranging from the simple to the complex. The most basic sentence element is the word. Larger units include phrases and clauses. Phrases contain neither a subject nor an object; together, they function as a verb, noun, adverb or adjective. Practice spotting the different types of phrases to increase your sentence know-how.
Spot prepositional phrases by the preposition that begins them: in the window, near the clock, after hours. They act as adjectives or adverbs modifying another part of the sentence. These are by far both the simplest and most common types of phrases.
Define infinitive phrases by their use of an infinitive (to + verb) plus a noun. They act like a noun, adjective or adverb. Try this example: To fly a kite was Bill's deepest joy. The infinitive phrase (to fly a kite) acts as a noun--in this case, the subject of the sentence.
Participle phrases have a participle (adjective made from a verb) plus an object. A present participle ends in -ing and forms phrases such as crying hysterically, marching with defiance, laughing like mad or scribbling furiously. A past participle ends in -ed (for regular verbs) or forms phrases such as beaten back or overcome with fear.
Gerund phrases contain a gerund (verb form ending in -ing) acting like a noun. Studying can be fun is an example of a sentence with a gerund (studying) as the subject. Luis got famous winning on Jeopardy is another example, with "winning on Jeopardy" serving as the gerund phrase.