Traditionally, a sentence is regarded as having a subject, an object and a verb, even if one of these is implied. The objects that modify the noun phrase collectively form the predicate of a sentence. An incomplete sentence is called a sentence fragment.

This is where the rubber of grammar meets the road of writing. By the time they start school, most children are speaking in complete sentences. As they learn to write, they begin to understand the structure behind what they are saying and as they learn more about this important building block they will be able to write more complex, colorful, and varied sentences.

One way to teach different types of sentences is to find examples of them in good literature and point them out to your children. You might also find that learning to diagram sentences will aid the understanding of different grammatical structures—then again, you may not!

Classification by structure:

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

• A simple sentence consists of a single independent clause with no dependent clauses.
• A compound sentence consists of multiple independent clauses with no dependent clauses. These clauses are joined together using conjunctions, punctuation, or both.
• A complex sentence consists of one independent clause with at least one dependent clause.
• A complex-compound sentence consists of multiple independent clauses, at least one of which has at least one dependent clause.

Classification by purpose:

Sentences can also be classified based on their purpose:

• A declarative sentence or declaration, the most common type, commonly makes a statement: "I am going home."
• An interrogative sentence or question is commonly used to request information: "When are you going to work?" (Rhetorical questions are different, posed for rhetorical effect—seeking to encourage reflection within the listener—rather than to elicit an answer: "How much longer must our people endure this injustice?")
• An exclamatory sentence or exclamation is generally a more emphatic form of statement: "What a wonderful day this is!"
• An imperative sentence or command is ordinarily used to make a demand or request: "Go do your homework."

Major and minor sentences:

A major sentence is a regular sentence; it has a subject and a predicate. For example: "I have a ball." In this sentence one can change the persons: "We have a ball." However, a minor sentence is an irregular type of a sentence. It does not follow all the grammatical rules; for example: "How do you do?" In this sentence one cannot change the person. It is a kind of greeting and saying "How do they do?" is not something one would normally express in a greeting. Other examples of minor sentences are headings, stereotyped expressions (Hello!), emotional expressions (Wow!), proverbs, etc. This can also include sentences which do not contain verbs (The more, the merrier) in order to intensify the meaning around the nouns (normally found in poetry and catchphrases).