Here's why:
* Clause: A clause is a group of words that contains a subject and a verb. It can be a complete thought (independent clause) or a partial thought (dependent clause).
* Sentence: A sentence is a complete thought that expresses a statement, question, command, or exclamation. It must have a subject and a verb.
Examples:
* Clause: "The cat sat on the mat." (independent clause, complete thought)
* Sentence: "The cat sat on the mat." (same as the clause above, complete thought)
* Clause: "Because the cat sat on the mat." (dependent clause, partial thought)
* Sentence: "The cat sat on the mat because the dog was sleeping." (two independent clauses connected to form a complete thought)
Key points:
* All independent clauses can stand alone as sentences.
* Dependent clauses cannot stand alone as sentences; they need to be attached to an independent clause to form a complete thought.
* Not all sentences are just one clause. Many sentences are made up of multiple clauses.
So, the statement you mentioned is backwards. It's true that all clauses can be sentences, but not all sentences are just single clauses.