A phrase is a group of words that work together as a single unit but do not contain a subject-verb pairing. They add meaning but cannot stand alone as a complete sentence. For example, 'in the park' or 'after the rain'.
A clause, on the other hand, is a group of words that includes a subject and a verb. Clauses can be independent (able to stand alone as a complete sentence) or dependent (not able to stand alone). For example, 'She runs fast' is an independent clause, while 'because she practices' is a dependent clause.
In summary, think of phrases as incomplete thoughts without a subject-verb component, while clauses contain that structure and can sometimes stand alone as a complete sentence.