A sentence is a word or a group of words that makes a complete sense and stands separate from any other grammatical construction. It begins with a capital letter and ends with a period (for statements), a question mark (for questions), or an exclamation mark (for exclamations). It is normally made up of a subject (an actor) and a predicate (what the actor does). But in some sentences, such as commands and exclamations, a single word or two words may stand as a sentence; that is, the subject or the predicate is not expressed, but it is understood. [e.g. Go. . Leave me. You again!: (You) go. (Ada) leave me. You (came) again!]
The systematic arrangement of words in the sentence is called syntax, which, as a field of grammatical study, examines the rules governing sentence-building, the correct order and agreement of words in the sentence structure.
- Sentence Parts: Subject and Predicate.
- Sentence Elements and Patterns: Structural Analysis.
- The order of Words (Parts and Elements) in the Sentence
- Question Tags: The Order/Pattern.
- Rules of Grammatical Concord: Subject-Verb agreement; Pronoun-Antecedent agreement; etc.
- Sentence Classification (by Intention and by Structure).
- Error in Sentence Structure.
There are two broad ways of classifying sentences:
- By intention.
- By structure.
(A) CLASSIFICATION BY INTENTION
This refers to the grouping of sentences according to the speaker’s intention or purpose of speaking. It can also be referred to as functional classification because it tells the communicative function or aim of any given utterance. By this type of classification, English recognises four major sentence types:
1. A Declarative or Assertive Sentence (i.e. a statement)
This makes a statement, declaring or asserting a fact/idea, in the affirmative (positive) or in the negative:
- You are a student. (positive statement)
- You are not a pupil. (negative statement)
Generally, the subject precedes the verb in declarative or assertive sentences.
2. An Imperative Sentence
Imperative sentences are used for giving directives, such as simple requests, commands, warnings, advice, or prohibitions. They may be in the affirmative (positive) or in the negative version:
- Go out. Please leave me. (positive)
- Don’t talk. Do not disobey God. (negative)
The subject of an imperative sentence is not obligatory; it is usually omitted, but it is understood to be the second person pronoun “You”.
3. An Interrogative Sentence
The Interrogative Sentence is used for asking question(s). It may be positive or negative:
- Who/what are you? (positive)
- Do you know me? (positive)
- Don’t you know me? (negative)
In an interrogative sentence, the operator (an auxiliary verb) comes before the subject except where the sentence begins with such question words as who, what, why, etc.
4. An Exclamatory Sentence
The exclamatory sentence expresses emotion or a strong/sudden feeling:
- You are great!
- Good heavens!
It may be short or incomplete but its import is usually strong and understood.
(B) CLASSIFICATION BY STRUCTURE
This refers to the grouping of sentences according to their structural arrangement/order, or the number and types of clauses in them. Below are seven outstanding sentence types based on structural classification:
1. Simple Sentence
A simple sentence is composed of only one subject and one predicate; that is, it is one main clause, which has only one finite verb. The subject or the predicate of the simple sentence may be simple, compound, or complete, provided that its modifier is not a clause that contains another finite verb.
- She smiled.
- One of the boys spoke Igbo during English lectures yesterday.
- Ibe and his friends did their youth service in Abuja.
2. Complex Sentence
A complex sentence consists of one main clause, with one or more subordinate clauses attached to it; that is, it contains one independent clause supported by one or more dependent clauses. The subordinate clause in a complex sentence may function as a sentence element or as a post modifier in a noun phrase.
- He said that he would visit us.
- The boy who beat your sister has escaped.
- He came here when he heard that you had travelled to Lagos because he didn’t want you to see him.
3. Compound Sentence
A compound sentence contains two or more main clauses joined by such coordinating conjunctions as and, but, or, etc. If it contains only two main clauses, it is called a double sentence. But if it contains three or more main clauses, it is referred to as a multiple sentence. Hence, a compound sentence may be double or multiple in terms of the number of main clauses in it.
- He came and we left. (double sentence)
- He came and we greeted him but he did not respond. (compound sentence)
4. A Compound – Complex Sentence
This comprises two or more main clauses, supported by one or more subordinate clauses.
- He came and we left because we didn’t want to participate in his discussion with our uncle.
- When Mary saw her husband coming home, she ran to him, embraced him and tried to kiss him but the man pushed her aside because he had heard of her extra marital affair with Chief Steve.
5. A Loose Sentence
A loose sentence is a complex or a compound-complex sentence which has its main clause(s) before its subordinate clause(s). One can, therefore, speak of a loose complex sentence (e.g. I shall visit you if you invite me when I have the time.) or a loose compound-complex sentence (e.g. The boy stared but was not stirred when his mistress chided him for not telling the truth).
6. A Periodic Sentence
A periodic sentence is an inverted version of the loose sentence. It is a complex or a compound-complex sentence whose subordinate clause(s)/details come before the main clause(s). Here, supporting details precede the main idea. In the periodic sentence, the introductory subordinate clause is usually marked off by comma to show that there should be a pause before the main clause that follows. We have periodic complex and periodic compound-complex sentence.
- Though he was the first to start eating, he was the last person to leave the dining table. (periodic complex sentence)
- Because the children were happy when I gave them biscuits, they sang sweet songs and danced to my tune. (periodic compound-complex sentence).
7. A Balanced Sentence
This is an antithetical structure in which parallel grammatical elements are put in a parallel structure. Usually, the sentence is made up of two parallel parts (words, phrases or clauses); the second part of the sentence mirrors, explains, contrasts, amplifies, or justifies,the first part.
- Reading maketh a full man; conference, a ready man. (balanced double sentence)
- Fair is foul and foul is fair. (balanced double sentence)