"Clause" vs. "phrase" vs. "sentence" [duplicate]

Solution 1:

Phrase, clause and sentence are three of the structural units that create meaning. A phrase is a word or words that don’t have much meaning on their own. If I suddenly utter the phrase My brother, you’ll wonder why I said it, but if I say My brother drives, you’ll feel I’ve said something that has meaning. There’s a completeness about it, because it contains the verb drives. That makes it a clause, but it is also a sentence. But I needn’t stop there. I can go on to say something else, almost without drawing breath. I can say My brother drives, but he doesn’t drive very well. I’ve added another clause, and together they, too, make a sentence, joined by the little word but. It is perhaps helpful to see two or more clauses joined together as a clause complex, although sentence in general use describes both single and multiple clauses.

Solution 2:

I think it's easier to define this in functional terms and not in semantic terms.

• A clause is a verb, together with all its complements, so that the unit is grammatically correct. The verb is always the nucleus of a clause.
• A phrase is any "functional group" of a clause.
• A sentence is one clause, or a group of clauses.

Of course, provided that the expressions have sense.

For example, the verb "to eat" needs a subject; thus, "to eat" isn't a clause, but "I eat" is. A more common clause perhaps is: "I eat pasta". The noun "pasta" works here as a direct object, but this object is optional: "I eat" is a correct clause because "pasta" isn't neccesary to get a grammatically correct one.

"I eat fresh pasta with my girlfriend" has three complements: "I" (subject), "fresh pasta" (direct object) and "with my girlfriend" (an adverbial). Only the subject is obligatory. They are all "phrases", and phrases are categorized by their nucleus: "I" and "fresh pasta" are nominal phrases, and "with my girlfriend" is a prepositional phrase. "Eat" isn't a complement but it is a "functional group", a "verbal phrase", as well as the other complements, whose role is to be the nucleus of the clause.

Any clause is also a sentence. The difference between clause and sentence makes sense when a complement is specified by means of other clause: "I know he likes me". "He likes me" is a clause working as a direct object of the main sentence.

To conclude, "He likes me" is a clause and a sentence while "I know he likes me" is a sentence but not a clause.

Solution 3:

It depends on your theory of syntax.

In most current non-generative theories of syntax, a sentence can be simple (i.e. it consists of one clause), complex (more than one clause, subordination), or compound (more than one clause, coordination).

A phrase cannot be used as a stand-alone utterance, e.g. "reading a book" is a phrase. However, with proper intonation etc., it can become a sentence, ("What are you doing"?) "Reading a book."

The word "go" can be a word (go), a phrase (go), a clause (Go!), and a sentence (Go!). For example, Alexander Reformatskij, a famous Soviet linguist, came up with the following Latin example: I! (=go.IMP.SG). This one letter/sound is a phoneme, a morpheme, a word, a phrase, a clause, and a sentence.

I believe that in generative theories of syntax there is no distinction between a sentence and a clause. In fact, the clause/sentence is a phrase itself (TP or CP or FP).