In Clauses, you learned that there are two types of clauses: independent and dependent. Recall that independent clauses are complete sentences because they have a subject and verb and express a complete thought. Dependent clauses, in contrast, cannot stand alone because they do not express a complete thought—even though they have a subject and a verb. Independent and dependent clauses can be used in a number of ways to form the four basic types of sentences: simple, compound, complex, and compound-complex. Time to make their acquaintance.