Depending on the number and types of clauses they contain, sentences are classified as
simple
compound
complex
compound-complex
Clauses come in two varieties: independent and subordinate.
An independent clause contains a subject and a predicate, and it either stands alone or could stand alone.
A subordinate clause also contains a subject and a predicate, but it functions within a sentence as an adjective, an adverb, or a noun; it cannot stand alone.
Simple sentence
A simple sentence is one independent clause with no subordinate clauses.
Compound sentence
A compound sentence is composed of two or more independent clauses with no subordinate clauses. The independent clauses are usually joined with a comma and a coordinating conjunction (and, but, or, nor, for, so, yet) or with a semicolon.
Complex sentence
A complex sentence is composed of one independent clause with one or more subordinate clauses.
Compound-complex sentence
A compound-complex sentence contains at least two independent clauses and at least one subordinate clause. The following sentence contains two independent clauses, each of which contains a subordinate clause.
Exercise: Sentence types
Related topics:
Subordinate clauses
Subjects
Verbs, objects, and complements
subject Grammatically, a word or word group that names who or what a sentence is about.
predicate A verb and its objects, complements, and modifiers.
subject Grammatically, a word or word group that names who or what a sentence is about.
predicate A verb and its objects, complements, and modifiers.
adjective A word that modifies or describes a noun or pronoun: lame, old, rare, beautiful; also the articles a, an, the.
adverb A word that modifies a verb, an adjective, or another adverb: very, smoothly, never.
noun The name of a person, place, thing, or an idea.
independent clause A word group containing a subject and a verb that can or does stand alone as a sentence.
subordinate clause A word group containing a subject and a verb that cannot stand alone as a sentence because it begins with a word that marks it as subordinate (such as although, because, who, or that).
independent clause A word group containing a subject and a verb that can or does stand alone as a sentence.
subordinate clause A word group containing a subject and a verb that cannot stand alone as a sentence because it begins with a word that marks it as subordinate (such as although, because, who, or that).
independent clause A word group containing a subject and a verb that can or does stand alone as a sentence.
subordinate clause A word group containing a subject and a verb that cannot stand alone as a sentence because it begins with a word that marks it as subordinate (such as although, because, who, or that).
independent clause A word group containing a subject and a verb that can or does stand alone as a sentence.
subordinate clause A word group containing a subject and a verb that cannot stand alone as a sentence because it begins with a word that marks it as subordinate (such as although, because, who, or that).