This lesson completes Unit 15X by introducing sentence classification by communicative function rather than clause structure. Lessons 151–155 classified sentences by how clauses are arranged. Lesson 156 now teaches that sentences can also be classified by what they do: declarative sentences state, interrogative sentences ask, imperative sentences command or instruct, and exclamative sentences express intensity or exclamation. This distinction is important because a sentence has both a structure and a function. For example, a sentence can be simple and interrogative, or complex and declarative. In English Language analysis, sentence function matters because it shapes how the writer addresses the reader, presents certainty, invites response, gives instruction, applies pressure or expresses intensity.

By the end of this lesson, students should be able to:

• identify declarative, interrogative, imperative and exclamative sentences;
• explain the difference between sentence structure and sentence function;
• and analyse how sentence functions shape address, certainty, urgency or emotional intensity.

Sentences can be classified by structure and by function. Structure asks how the sentence is built from clauses. Function asks what the sentence does. A declarative sentence makes a statement. An interrogative sentence asks a question. An imperative sentence gives a command, instruction or request. An exclamative sentence expresses strong feeling or intensity. Writers choose sentence functions to guide how the reader responds.

• Theme: The general topic of the text
• Sentence Form: what a grammatical unit like a sentence takes (simple, compound, complex).
• Sentence function: the communicative job a sentence performs.
• Declarative sentence: a sentence that makes a statement.
• Interrogative sentence: a sentence that asks a question.
• Imperative sentence: a sentence that gives a command, instruction or request.
• Exclamative sentence: a sentence that expresses strong feeling or intensity.
• Rhetorical question: a question asked for effect rather than to receive an answer.

• This sentence is declarative/interrogative/imperative/exclamative because…
• The sentence function is…
• The sentence structure is…, but the function is…
• The interrogative sentence makes the reader…
• The imperative sentence creates urgency by…
• The declarative sentence presents the idea as…
• This function affects meaning because…

Sentence structure and sentence function are different classification systems. “Close the door” is structurally simple because it contains one main clause, but functionally it gives a command. A sentence can therefore have two labels at once.

Imagine two texts sharing the same form of advertising, and shar the theme of road accidents, but perform different functions; one shows a story of a car crash and the other provides information about road accident statistics. Both adverts look very different, because one is descriptive and the other informative.

Maybe two texts share in their form of advertising, on the same theme of fast food, but one functions as a warning against unhealthy eating and the other is advertising a fast food chain.

The road is unsafe (declarative sentence presenting a claim as fact). How many more accidents must happen? (interrogative sentence, likely rhetorical, pressuring the reader). Sign the petition today (imperative sentence telling the reader what to do).

The writer uses different sentence functions to guide the reader’s response. The declarative sentence “The road is unsafe” presents the issue as certain. The interrogative sentence “How many more accidents must happen?” pressures the reader by asking a rhetorical question. The imperative “Sign the petition today” then turns concern into action. The sentence functions move the reader from belief, to urgency, to response.

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The river path has been closed for six months (declarative sentence presenting information). Local residents have reported broken lights, loose fencing and deep water beside the bank (declarative sentence presenting evidence). Why has nothing changed? (interrogative sentence challenging authority). Do not wait for another accident before taking action (imperative sentence directing the reader). Come to the meeting on Thursday and ask the council for a clear repair date (imperative sentence giving a specific action). What a difference a safe path would make for children, runners and older residents who use it every day (exclamative sentence expressing intensity and positive possibility).

The writer uses sentence function to move from information to pressure and action. The opening declarative sentences present the closure and safety problems as factual. The interrogative “Why has nothing changed?” challenges the lack of progress and encourages the reader to share frustration. The imperative sentences “Do not wait” and “Come to the meeting” then direct the reader towards action. Finally, the exclamative sentence “What a difference a safe path would make” expresses intensity and hope. The functions create a persuasive sequence: evidence, challenge, instruction and emotional possibility.