There is an evident difference between phrases and clauses.
Phrases: a phrase is a group of related words lacking a subject and a predicate.
Clauses: a clause is a group of related words containing both a subject and a predicate.
Both phrases and clauses are main bases of constructing a sentence. When combined with other parts of speech, they help build an elaborate system that carry away your meaning. Recognizing the difference between the two main bases of a sentence is essential to build a correct and well composed sentences.
A phrase is often defined as a group of related words that lacks subject and verb integration and does not form a predicate. It can contain a noun or a verb. Mainly, a phrase can provide additional information or add more context to the sentences you write. A phrase can never stand alone as a sentence; however, a phrase can lodge itself inside clauses that are either complete sentences on their own or ones that are dependent on the rest of the sentence. When a phrase is within a clause, it functions as a part of speech.
Phrases are generally grouped as follows:
- Verb Phrases - Infinitive Phrases
- Noun Phrases - Participial Phrases
- Gerund Phrases - Prepositional Phrases
Clauses are the building blocks of sentences. A clause is a group of related words containing a subject and a verb. It can be simply distinguished from a phrase, which is a group of related words that does not contain a subject-verb relationship, such as "in the evening" or "walking down the street" or "having grown used to this ill treatment.” Like phrases, clauses are also classified as restrictive and nonrestrictive clauses. A nonrestrictive clause is not essential to the meaning of the sentence; it can be removed from the sentence without changing its basic meaning.
There are two kinds of clauses: independent and dependent. Clauses are combined by three groups of words to form different kinds of sentences: coordinators, subordinators, conjunctive adverbs, and by means of a semicolon.
A more detailed study is found in my ebook "Sentence Structure Guide" which is available on Apple iTunes and iBookstore.