The document discusses clauses and their two types: independent and dependent clauses. Independent clauses can stand alone as a complete sentence since they have a subject and verb and express a complete thought. Dependent clauses also have a subject and verb but do not express a complete thought on their own and need to be connected to an independent clause. Dependent clauses often begin with dependent markers like "after", "although", "because", etc. and cannot stand alone as sentences but must be joined with an independent clause.