What Is a Complete Sentence?
In standard English, a complete sentence
- must have a subject and a verb and
- must stand on its own; that is, it is a complete thought without needing another sentence to complete the idea.

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For example, “It was raining” is a complete sentence. The subject is “it,” and the verb is “to rain.”
However, “because it was raining,” has a subject and a verb, but it is not a complete sentence because it does not make sense on its own. It is part of another clause, for example, “I stayed home because it was raining.”
Examples of complete sentences
John fell.
John tripped over a bowl.
John dropped a bowl.
John dropped the bowl on the floor.
John was cooking.
Each of these statements is a complete sentence. It has a subject (John) and a verb (to fall, to drop, to cook), and it makes sense on its won without needing another clause to complete it.
Independent and Dependent Clauses
Let’s build on the first complete sentence, “John fell,” as the starting point. We could add the time the action occurred. That would answer the question, “When did John fall?”
John fell [time?]
John fell yesterday.
From the previous examples, we actually know it happened when he tripped over a bowl. Adding that information to the basic sentence would produce
John fell when he tripped over a bowl.
You should notice that, on its own, “he tripped over a bowl” is a complete sentence; however, if you say, “when he tripped over a bowl," it no longer makes sense by itself. You would wonder, “When he tripped over a bowl… what happened?
In addition, the complete sentence is still “John fell,” and “when he tripped over a bowl” now works as an adverb (specifically, a time adverb) showing the time the action occurred.
You now have an independent clause, “John fell” and a dependent clause (specifically, an adverbial clause) attached to it. The adverbial clause depends on the independent clause to make sense. That is why that part of the sentence is called a dependent clause.
Adding Complexity
You can make a sentence more and more complex by adding dependent clauses to it. For example, let’s build on “John fell when he tripped over the bowl.” by describing the bowl (or adding information that clarifies the bowl). We know it was the bowl he had dropped on the floor. Let’s add that information to it
John fell when he tripped over the bowl [which bowl?].
John fell when he tripped over the bowl that he had dropped on the floor.
We also know that when he dropped the bowl (while he was cooking).
John fell when he tripped over the bowl that he had dropped on the floor [when?]
John fell when he tripped over the bowl that he had dropped on the floor while he was cooking
Things to Note
As we saw earlier, “John fell” is a complete sentence. We kept adding other parts to it clarify other portions of the statement.
“John fell” was then the independent clause, to which we added other, dependent clauses.
You could say that “John fell” remains the basic statement, or the independent clause, which is part of a more complex sentence structure.
When Is it Too Much?
In theory, you can keep adding dependent clauses to a basic sentence infinitely, thus making it more and more complex. However, our human brains cannot deal with very much information before we start losing track of what the ideas are. Creating sentences are useless when they are so complex that people cannot understand them.
Compared to many other languages, we tend avoid overly complex sentences in written English. If a sentence starts getting too long and complex, we break it up into shorter ideas.
Importance of identifying the independent clause
When you understand the parts of a sentence and how they go together, you can identify the independent clause, the main portion of a statement.
You then make decisions about punctuation, verb-subject agreement, verb tenses to use, and so forth. Look at the verb in the following sentence. Should it be “benefit” or “benefits?” That depends on the subject, that is, who or what benefits from something.
Students planning to follow a science career, which has become popular in the last decade, benefit / benefits from advanced math courses.
If you understand the parts of the sentence, you can identify the basic sentence (the independent clause) as “Students benefit from advanced math courses.” The subject is “students,” and they are the ones benefitting from advanced math courses.
The structure of the sentence is
Students [[clarify “students"], [clarify “science career"],] benefit / benefits from advanced math courses.
Continue the Lesson
Continue the lesson to learn about the types of dependent clauses you can use to build complex sentences...