Every piece of English writing is built from sentences. Understanding what a sentence is — and how sentences can be joined together — is the foundation of all writing and speaking. This session explores the simplest sentence types: simple sentences (one complete idea) and compound sentences (two complete ideas joined together). Mastering these gives teachers a solid base for teaching all writing at every level.
Before you start — think honestly about your own teaching and experience.
Look at the examples. Answer each question before reading the explanation — this is how your students will learn too.
Read these groups of words. Some are complete sentences. Some are not. Can you identify which are complete and which are incomplete — and explain what is missing from the incomplete ones?
A complete sentence (also called an independent clause) needs two essential things: a subject (who or what the sentence is about) and a finite verb (the main action or state — in a tense). 'She teaches at the village school' — subject: she. Verb: teaches. Complete. 'Because the rain was heavy' — this has a subject (rain) and a verb (was) but it is not complete because 'because' makes it dependent on another clause. It raises the question 'what happened because of the rain?' — and that answer is missing. 'Running to the market every morning' — no subject, no finite verb. A fragment. 'After the long meeting' — no subject, no finite verb. A fragment. Understanding what makes a complete sentence is one of the most practical grammar skills a teacher can develop, because incomplete sentences (fragments) are one of the most common writing errors students make at all levels.
Now read these pairs of simple sentences. Then read the compound sentence that follows. What has joined the two simple sentences? What word has been used, and where is the comma?
Each compound sentence joins two independent clauses using a coordinating conjunction: and, but, or, yet. Each side of the conjunction is a complete, independent sentence on its own. A comma appears BEFORE the conjunction (not after). This is the standard rule in formal written English: comma + coordinating conjunction joins two independent clauses. The coordinating conjunctions are: and (addition), but (contrast), or (alternative), so (result), yet (contrast — similar to but, slightly more formal), for (reason — more formal and literary), nor (addition of negative — 'she didn't come, nor did she explain'). These are sometimes remembered with the acronym FANBOYS: For, And, Nor, But, Or, Yet, So.'
Now read these sentences. Identify any problems with how the sentences are joined — or not joined.
Sentence 1: COMMA SPLICE — two independent clauses joined only by a comma, with no conjunction. A comma alone cannot join two sentences. Fix: 'She worked hard, so she passed her exams.' Or use a full stop: 'She worked hard. She passed her exams.' Sentence 2: AND OVERUSE — joining too many clauses with 'and' produces a breathless, monotonous text. Fix: use a variety of conjunctions and sentence lengths. Sentence 3: MISSING COMMA — in a compound sentence, the comma comes BEFORE the conjunction: 'She was tired, but she continued teaching.' Sentence 4: FRAGMENT — 'Although she was tired' is not a complete sentence. The conjunction 'although' makes it dependent on the main clause. These two parts need to be joined: 'Although she was tired, she continued teaching.' This distinction (although = subordinating conjunction → complex sentence) is covered in the next lesson.'
| Tense / Form | Use / Meaning | Example | Key time words |
|---|---|---|---|
| Simple sentence | One independent clause — subject + finite verb | She teaches mathematics at the secondary school. | No conjunction needed |
| Compound sentence (and) | Two independent clauses — addition or continuation | She teaches mathematics, and her students perform very well. | Comma + and |
| Compound sentence (but) | Two independent clauses — contrast or unexpected result | She tried to explain, but the students were confused. | Comma + but |
| Compound sentence (so) | Two independent clauses — result or consequence | It was raining heavily, so the lesson moved inside. | Comma + so |
| Compound sentence (or) | Two independent clauses — alternative or choice | She can stay late to help, or she can come early tomorrow. | Comma + or |
THE COORDINATING CONJUNCTIONS — FANBOYS:
For — gives a reason (formal and literary):
And — adds information or continues:
Nor — adds a negative (used after a negative clause):
But — shows contrast or unexpected result:
Or — shows alternatives or choices:
Yet — shows contrast (similar to but — slightly more formal or emphatic):
So — shows result or consequence:
THREE COMMON ERRORS TO ADDRESS FIRST:
1. Comma splice: joining two sentences with only a comma ('She came, she saw.') → wrong. Use a conjunction: 'She came, and she saw.'
2. Missing comma: 'She tried but she failed.' → 'She tried, but she failed.' Comma goes BEFORE the conjunction.
3. Fragment: 'Because it was raining.' is not a sentence. It must attach to a main clause.
Does the group of words have a subject AND a finite verb AND express a complete idea? → simple sentence. Are there two complete sentences joined by and/but/or/so/yet/for/nor? → compound sentence. Is there a comma before the conjunction? → should be. Are two complete sentences joined only by a comma? → comma splice — add a conjunction. Is the conjunction 'although', 'because', 'when', 'if'? → NOT a coordinating conjunction — this creates a complex sentence, covered in the next lesson.
Choose the correct coordinating conjunction to complete each compound sentence. Think about the meaning relationship between the two clauses.
Each sentence contains an error. Write the correct version and explain why — then reveal the answer.
Use this sequence directly in class — guided discovery, no textbook needed. Tap each step to mark it done.
STEP 1 — WHAT IS A SENTENCE? (5 minutes): Write five groups of words on the board — some complete sentences, some fragments. Students work in pairs to decide: complete or incomplete? For each incomplete one, ask: what is missing? (Subject? Finite verb? Something to complete the idea?) Build the definition together: a complete sentence has a subject, a finite verb, and expresses a complete idea.
STEP 2 — SIMPLE SENTENCES FIRST (5 minutes): Ask students to write five simple sentences about their school — one idea each. Share them. Confirm: each has a subject and a finite verb. Each expresses one complete idea. These are simple sentences — the building blocks of all writing.
STEP 3 — COMBINING WITH FANBOYS (8 minutes): Write the seven conjunctions on the board: For / And / Nor / But / Or / Yet / So. Give students five pairs of simple sentences. They must join each pair using the most appropriate conjunction — and add a comma before the conjunction.
STEP 4 — COMMA SPLICE HUNT (5 minutes): Write six compound sentences — three with correct commas, three with comma splices. Students identify and correct the comma splices. Name the error: 'This is a comma splice — two sentences joined only by a comma. A conjunction is needed.'
STEP 5 — WRITING PRACTICE (5 minutes): Ask students to write a short paragraph (5–6 sentences) about their school — using a mix of simple sentences and compound sentences. They must use at least three different conjunctions. Share and compare. Listen for comma splices and fragments — address as a group.
Use directly in class — copy, adapt, or read aloud. No printing needed.
For each strategy, choose the option that best describes where you are now.
Your feedback helps other teachers and helps us improve TeachAnyClass.