Grammar Fundamentals – IEO Study Notes
Simple, Compound & Complex Sentences
Target exam: IEO 2013‑2024, IIT‑JEE (English), GRE, SAT, and other competitive exams.
Goal: Rapid identification, transformation, and creation of accurate sentences for high‑stakes written tests.
1. Quick Reference Cheat‑Sheet
| Sentence Type | # of Independent Clauses | # of Dependent Clauses | Typical Conjunctions | Punctuation Rule |
|---|---|---|---|---|
| Simple | 1 | 0 | — | No comma required (unless introductory element) |
| Compound | ≥2 | 0 | Coordinating: for, and, nor, but, or, yet, so (FANBOYS) | Comma before coordinating conjunction when clauses are long or contain internal commas |
| Complex | 1 | ≥1 | Subordinating: because, although, if, while, when, after, before, since, unless, etc. | Comma before subordinate clause only if it is non‑essential or at the beginning of the sentence |
Remember:
A sentence is compound if it has two or more independent clauses joined by a coordinating conjunction.
A sentence is complex if it has one independent clause plus at least one subordinate clause.
A sentence can be both compound‑complex (two or more independent clauses + at least one subordinate clause).
2. Detailed Explanations
2.1 Simple Sentences
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Definition: One independent clause (subject + predicate).
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Structure Pattern:
[Subject] + [Verb] + [Object/Complement] (+ optional modifiers) -
Examples:
- The cat slept.
- She reads books.
- They will finish the project tomorrow.
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Tricky Points:
- A simple sentence may have multiple verbs (compound predicate) but only one subject.
- I went to the market and bought apples. – It looks like two clauses, but the second verb is a conjoined predicate; the whole is still a simple sentence.
- Avoid dangling modifiers – they create confusion about which subject the modifier refers to.
2.2 Compound Sentences
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Definition: Two or more independent clauses joined by a coordinating conjunction (FANBOYS) or by a semicolon.
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Structure Pattern:
Clause 1 (S+VP) + (Comma?) + Coordinating Conjunction + Clause 2 (S+VP) -
Examples:
- I wanted to go, but the rain started.
- She studied hard; she passed the exam.
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Punctuation Rules:
- Comma + Coordinating Conjunction when clauses are long or