In Section 1.2, you learned that a subject and a verb make up an independent clause or a complete sentence. You also learned that a dependent clause is a clause which starts with a dependent marker (when, after, before) and contains a subject and a verb. In Section 1.3, you will learn about four different types of sentences and the punctuation associated with each sentence. During this lesson, it will be important to memorize the four sentence types because understanding them will help you punctuate them correctly.

Simple Sentences

The first sentence type is a simple sentence. A simple sentence contains one independent clause with a subject and a verb. In the examples below, the subjects are bolded and the verbs are underlined to help you see this structure.

• Melissa ran to catch the bus.
• He jumps onto his skateboard.
• She laughs aloud.

Remember to always capitalize the first letter of every sentence and place a period, question mark, or exclamation mark at the end of a sentence.

Now go to Section 1.3a: Simple Sentences Practice in the Lesson One Assignments folder to practice writing a few simple sentences. A PDF version

Compound Sentences

The second sentence type is a compound sentence. These sentences contain two independent clauses connected by a coordinating conjunction. There are only seven coordinating conjunctions in the English language: and, or, nor, for, yet, but, and so. Coordinating conjunctions help link the two independent clauses together. As you carefully look at the examples below, notice that a comma always comes before a coordinating conjunction:

The comma helps give some separation between the two independent and complete thoughts that make up the sentence, while the coordinating conjunction shows how they link together. In the example "John traveled to Texas," the writer of the sentence wanted to expand on that complete thought about John's travels, so he added a comma and "yet" to help us understand the connection between the first complete thought and the next one: "he did not see any cowboys."

Another way to produce a compound sentence is with two independent clauses and an independent marker[3]. An independent marker is a connecting word just like and, but, so, and yet, except that that the independent marker conveys a more complex connection between the two independent clauses. Look at these examples of independent markers:

In the examples below, notice that a semicolon is used before the independent marker and a comma is placed after it:

Here the semicolon helps separate the two independent clauses or complete thoughts. Think of the semicolon as a stronger separation between the thoughts than the comma was in the previous examples ("John traveled to Texas, yet he did not see any cowboys"). We use that stronger stop because of the independent markers.

Be sure to memorize when to use a comma to separate two independent thoughts (with coordinating conjunctions) and when to use a semicolon (with independent markers).

Go to Section 1.3b: Compound Practice Sentences in the Lesson One Assignments folder to practice writing a few compound sentences. A PDF version

Complex Sentences

The third sentence type is a complex sentence. This type of sentence contains one independent clause and a dependent clause. Remember, in Section 1.2, you learned that dependent clauses start with any of these dependent markers:

As you look at the examples below, pay careful attention to the dependent clause because it can be located in the front, back, or middle of a sentence. (Adjective clauses, which are introduced in Section 1.4, are also found in the back or middle of a complex sentence.)

Dependent clause introducing a sentence

Notice how a comma always comes after the dependent clause, setting it apart from the independent clause/complete sentence. When the dependent clause introduces a sentence, we use a comma to signal to the reader that it is just an introductory thought and not the main part of the sentence. For example, "her parents picked her up" is the main thought/action of the first example. The clause "after Jane went to the party" tells us when the main thought/action of the sentence occurred.

Dependent clause at the end of a sentence

Notice that these sentences do not use a comma to separate the independent clause from the dependent one. The main part of the sentence comes first, and the dependent clause follows naturally—there's no need to signal to the reader that the dependent clause is the subordinate or lesser idea because it comes last in the sentence.

Dependent clause in the middle of a sentence

One way a complex sentence appears is with one independent clause split in half and nonessential information stuffed in the middle. Nonessential means the sentence still makes sense if the nonessential content is missing. This is also called a nonrestrictive clause. Here are a few examples:

In these examples, the commas appear in front and behind the nonessential information clause, showing that the words can easily slip in and out of the sentence without changing the overall meaning of the sentence. The commas signal to the reader that the information is "extra" and not necessary to the main thought of the sentence.

Go to Section 1.3c: Complex Sentence Practice in the Lesson One Assignments folder to practice complex sentences. A PDF version

Compound-Complex

The fourth sentence type is compound-complex. As the name suggests, the compound-complex sentence combines two sentence types—it has two independent clauses (just like the compound sentence) and at least one dependent clause (just like the complex sentence). Here are a few examples:

Dependent Clause Introducing Two Independent Clauses

Note: The underlined sentences show the separate independent clauses.

In this example, the dependent clause appears first and the compound sentence appears second. The dependent clause is separated from the rest of the sentence to signal the reader that it is just an introductory thought and not the main part of the sentence.

Dependent Clause After Two Independent Clauses

Note: The underlined sentences show the separate independent clauses.

In this example, the compound sentence appears at the beginning of the sentence and connects to the dependent clause. Notice that the dependent clause is not offset by a comma because it comes at the end of the sentence. Many native English speakers would be tempted to put a comma between date and although because there seems to be a natural pause when you read this sentence aloud. Grammatically speaking, however, a comma is not necessary there.

Dependent Clause Between Two Independent Clauses

The dependent clause can also appear between the two independent clauses as a kind of interruption.

The commas appear around the dependent clause to signal to the reader that this is extra information. Remember that the word so is a coordinating conjunction, so it links two equally important complete thoughts. Although is a subordinating conjunction.

See Section 1.3d: Compound Complex Sentence Practice in the Lesson One Assignments folder for compound-complex practice sentences. A PDF version

If you would like to see more examples of the different sentence types, you can look at the sidebar on page 340 of your textbook.

Assignment 1.3

After you have finished the practice exercises, complete the Assignment 1.3 Quiz in the Lesson One Assignments folder.

[3] Independent markers are also known as conjunctive adverbs, so if you want to find more information about this topic, you can use that term to expand your search. "Conjunctive" tells us that the word acts as a connector. Adverbs, as you may know, tell us when, where, why, under what conditions, or to what extent something occurs. So, a conjunctive adverb describes more of the relationship between two independent clauses than a coordinating conjunction does.