Sentence and Classifications

A sentence can also be defined in orthographic terms alone, i.e. as simply that which is contained between a capital letter and a full stop. This is arguably more accurate than definitions which conflate orthography and grammar, given the variety of structures which are possible between the capital letter and a full stop.

The Sentence will be classified into 2 clauses


By structure

       One traditional scheme for classifying English sentences is by the number and types of finite clauses:

Ø       A simple sentence consists of a single independent clause with no dependent clauses.

Ø       A compound sentence consists of multiple independent clauses with no dependent clauses. These clauses are joined together using conjunctions, punctuation, or both.

Ø       A complex sentence consists of at least one independent clause and one dependent clause.

Ø       A complex-compound sentence (or compound-complex sentence) consists of multiple independent clauses, at least one of which has at least one dependent clause.
 
By purpose

     Sentences can also be classified based on their purpose:

Ø      A declarative sentence or declaration, the most common type, commonly makes a statement: "I have to go to work."

Ø      An interrogative sentence or question is commonly used to request information — "Do I have to go to work?" — but sometimes not; see rhetorical question.

Ø      An exclamatory sentence or exclamation is generally a more emphatic form of statement expressing emotion: "I have to go to work!"

Ø      An imperative sentence or command tells someone to do something (and if done strongly may be considered both imperative and exclamatory): "Go to work." or "Go to work!"

Simple Sentence

A simple sentence, also called an independent clause, contains a subject and a verb, and it expresses a complete thought. In the following simple sentences, subjects are in yellow, and verbs are in green.  

A. Some students like to study in the mornings. B. Juan and Arturo play football every afternoon. C. Alicia goes to the library and studies every day.

The three examples above are all simple sentences.  Note that sentence B contains a compound subject, and sentence C contains a compound verb.  Simple sentences, therefore, contain a subject and verb and express a complete thought, but they can also contain a compound subjects or verbs.

COMPOUND SENTENCE

A compound sentence contains two independent clauses joined by a coordinator. The coordinators are as follows: for, and, nor, but, or, yet, so. (Helpful hint: The first letter of each of the coordinators spells FANBOYS.) Except for very short sentences, coordinators are always preceded by a comma. In the following compound sentences, subjects are in yellow, verbs are in green, and the coordinators and the commas that precede them are in red. 

A.  I tried to speak Spanish, and my friend tried to speak English.  B.  Alejandro played football, so Maria went shopping.  C.  Alejandro played football, for Maria went shopping.

The above three sentences are compound sentences.  Each sentence contains two independent clauses, and they are joined by a coordinator with a comma preceding it.  Note how the conscious use of coordinators can change the relationship between the clauses.  Sentences B and C, for example, are identical except for the coordinators.  In sentence B, which action occurred first?  Obviously, "Alejandro played football" first, and as a consequence, "Maria went shopping.  In sentence C, "Maria went shopping" first.  In sentence C, "Alejandro played football" because, possibly, he didn't have anything else to do, for or because "Maria went shopping."  How can the use of other coordinators change the relationship between the two clauses?  What implications would the use of "yet" or "but" have on the meaning of the sentence?

COMPLEX SENTENCE

A complex sentence has an independent clause joined by one or more dependent clauses. A complex sentence always has a subordinator such as because, since, after, although, or when or a relative pronoun such as that, who, or which. In the following complex sentences, subjects are in yellow, verbs are in green, and the subordinators and their commas (when required) are in red.

A. When he handed in his homework, he forgot to give the teacher the last page.  B. The teacher returned the homework after she noticed the error. C. The students are studying because they have a test tomorrow. D. After they finished studying, Juan and Maria went to the movies. E. Juan and Maria went to the movies after they finished studying.

When a complex sentence begins with a subordinator such as sentences A and D, a comma is required at the end of the dependent clause. When the independent clause begins the sentence with subordinators in the middle as in sentences B, C, and E, no comma is required. If a comma is placed before the subordinators in sentences B, C, and E, it is wrong.
Note that sentences D and E are the same except sentence D begins with the dependent clause which is followed by a comma, and sentence E begins with the independent clause which contains no comma.  The comma after the dependent clause in sentence D is required, and experienced listeners of English will often hear a slight pause there.  In sentence E, however, there will be no pause when the independent clause begins the sentence.