There are three types of sentences in English:
1. Simple sentence
2. Compound sentence
3. Complex sentence
1. 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.
The three examples above are all simple sentences. Note that sentence 2 contains a compound subject, and sentence 3 contains a compound verb. Simple sentences, therefore, contain a subject and verb and express a complete thought, but they can also contain compound subjects or verbs.
2. 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.
In sentence 3, “Alejandro played football” because, possibly, he didn’t have anything else to do, for or because “Maria went shopping.” In sentence 2, which action occurred first? Obviously, “Alejandro played football” first, and as a consequence, “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 meaning of the sentences. Sentences 2 and 3, for example, are identical except for the coordinators.
3. 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 (and many others) 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.
Note that sentences 4 and 5 are the same except sentence 4 begins with the dependent clause which is followed by a comma, and sentence 5 begins with the independent clause which contains no comma. The comma after the dependent clause in sentence 4 is required, and experienced listeners of English will often hear a slight pause there. In sentence 5, however, there will be no pause when the independent clause begins the sentence.When a complex sentence begins with a subordinator such as sentences 1 and 4, 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 2, 3, and 5, no comma is required. If a comma is placed before the subordinators in sentences 2, 3, and 5, it is wrong.
Click this link for the chart Types of Sentences Chart or you can watch this video from Shmoop. It’ll teach you the types of sentences in a simpler way.