Complex Sentences Worksheet

Lesson Overview

About this worksheet

A complex sentence joins an independent clause (a complete sentence) with a dependent clause (one that cannot stand alone) using a subordinating conjunction such as because, although, when, if, since, while, after, before, or until. When the dependent clause comes first, a comma follows it; when it comes second, usually no comma. Complex sentences let writers show how ideas relate – cause, time, condition, contrast – and they are the next step beyond the compound sentence.

Section A on page 1 gives eight sentences and asks the student to label each simple or complex. The set alternates one-clause simple sentences (The dog buried the bone; Maya read a book) with complex sentences that begin with or contain a subordinating conjunction (When the alarm rang…; …because the wind was strong), so students learn to spot the subordinating word that signals a dependent clause.

Section B on page 2 raises the difficulty: each of six items gives two clauses AND a subordinating conjunction in parentheses (when, because, although, if, until, before), and the student combines them into one complex sentence. Because some items place the dependent clause first and some second, students practice both the comma-after and no-comma patterns from the reference box.

Page 3 is a complete answer key. Section A lists simple or complex for each sentence; Section B gives a sample complex sentence for each pair. The reference box at the top of page 1 defines independent and dependent clauses, lists the common subordinating conjunctions, explains the comma rule, and shows a because-it-rained example that is not reused in any assessed item.

How to Use This Lesson

Read the reference box aloud and contrast an independent clause (can stand alone) with a dependent clause (begins with because, when, if…). Show both because-it-rained examples.

Work Section A item 1 together: ‘The dog buried the bone’ is one complete clause, so it is simple. Item 2 (‘When the alarm rang, everyone left the building’) has a dependent clause, so it is complex.

Assign the rest of Section A independently. Remind students that a subordinating word (because, although, when, if) signals a complex sentence.

Demonstrate Section B item 9 together: ‘The power went out. We lit some candles. (when)’ -> ‘When the power went out, we lit some candles’ (comma after the opening dependent clause).

Use the answer key on page 3 for self-check or aide spot-check; any combination using the conjunction with correct comma placement counts.

Pair with the Compound Sentences Worksheet or the Conjunctions Worksheet to build a sentence-structure mini-unit.

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