Grammar Worksheets

Mastering Complex Sentences: Guide, Exercises, and Answer Keys

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Published on by Alma Webster • Revised on
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A2 EnglishB1 English

Complex sentences help writers express deeper ideas by showing cause, time, contrast, and more! On this page, you’ll find printable worksheets and exercises that help students combine ideas using subordinating conjunctions like because, since, after, and while.

Complex Sentence Quick Guide

Dependent clause position Structure Example
Dependent clause first Subordinator + Dependent Clause, Main Clause Because it rained, we stayed home.
Dependent clause last Main Clause + Subordinator + Dependent Clause We stayed home because it rained.

Comma tip: If the dependent clause comes first, use a comma. If the main clause comes first, no comma is needed.

Download Complex Sentence Worksheets

1. Turn the simple sentence into a complex sentence and highlight the adverbial clause.

Complex sentences worksheet: turn simple sentences into complex sentences and highlight the adverb groupPin

2. Mark MC if the clause is the main clause and DC if it is a dependent clause. Then, complete the complex sentence by adding another clause.

Complex sentence worksheet: label MC main clause or DC dependent clause and complete each complex sentencePin

Answer key:

Answer key for complex sentence worksheet: MC and DC labels with completed complex sentencesPin

3. Read each sentence and tick the independent clause.

Complex sentences worksheet: identify and tick the independent clause in each sentencePin

4. Choose the correct subordinating conjunction (SWABI) to combine the independent clauses into one complex sentence.

SWABI complex sentence worksheet: choose the correct subordinating conjunction to combine clausesPin

5. Choose the words from the word bank to complete the sentences.

Complex and compound-complex sentences worksheet: use the word bank to complete the sentencesPin

6. Read each sentence and record the independent clause beneath it.

Complex sentence worksheet: write the independent clause for each sentencePin

Download Complex Sentence Worksheets PDF

Complex Sentence Exercises

Exercise 1: Combine the Sentences

Direction:

Each pair of sentences contains two independent ideas. Combine them into one complex sentence using an appropriate subordinating conjunction such as:
although, since, because, if, while, before, after, unless, when, even though, so that, until.

Sentence Pairs to Combine:

  1. She was feeling sick. She went to school.
  2. He listens to music. He does his homework.
  3. We arrived at the airport. The flight had already left.
  4. I won’t go to the party. You invite me.
  5. They started cooking. They washed their hands.
  6. My sister reads quietly. I play video games.
  7. He didn’t bring an umbrella. It was raining.
  8. We left early. We wouldn’t miss the bus.
  9. She smiled. She was nervous.
  10. You can’t watch TV. You finish your homework.

Sample Answer Key:

No. Combined Complex Sentence
1 Although she was feeling sick, she went to school.
2 He listens to music while he does his homework.
3 When we arrived at the airport, the flight had already left.
4 I won’t go to the party unless you invite me.
5 They washed their hands before they started cooking.
6 My sister reads quietly while I play video games.
7 He didn’t bring an umbrella even though it was raining.
8 We left early so that we wouldn’t miss the bus.
9 Although she was nervous, she smiled.
10 You can’t watch TV until you finish your homework.

Exercise 2: Rewrite the Sentence

Direction:

Each sentence below is a simple sentence. Rewrite it to make it a complex sentence by adding a subordinating clause. You can add your own ideas, but make sure your new sentence uses a subordinating conjunction like:
because, although, since, if, when, after, while, unless, before, even though.

Simple Sentences to Rewrite:

  1. I stayed home.
  2. The baby is crying.
  3. She smiled at me.
  4. We missed the bus.
  5. The dog barked.
  6. He didn’t go to the party.
  7. I studied all night.
  8. They built a sandcastle.
  9. I took a photo.
  10. The kids are playing.

Sample Answer Key:

No. Complex Sentence Example
1 I stayed home because I wasn’t feeling well.
2 The baby is crying because she is hungry.
3 She smiled at me although she looked tired.
4 We missed the bus since we left the house late.
5 The dog barked when the mailman arrived.
6 He didn’t go to the party because he had a lot of homework.
7 I studied all night so that I could pass the test.
8 They built a sandcastle while the tide was low.
9 I took a photo before the sun went down.
10 The kids are playing although it’s almost time for dinner.

Exercise 3: Correct the Mistake

Direction:

Each sentence below contains a mistake with a subordinating conjunction or sentence structure. Read carefully, then rewrite the sentence correctly.

Sentences with Mistakes:

  1. Because she was tired. She went to bed early.
  2. I stayed home although I was sick.
  3. If you will study, you get a good grade.
  4. He cleaned the house after he will eat dinner.
  5. While I was cooking. My phone rang.
  6. The baby cried since she is hungry.
  7. Unless you don’t hurry, you’ll miss the bus.
  8. I’ll wait when you arrive.
  9. Even though he was late but he finished his work.
  10. Before we went to school we eats breakfast.

Answer Key (Corrected Sentences):

No. Corrected Sentence
1 Because she was tired, she went to bed early.
2 I stayed home because I was sick.
3 If you study, you will get a good grade.
4 He cleaned the house after he ate dinner.
5 While I was cooking, my phone rang.
6 The baby cried since she was hungry.
7 Unless you hurry, you’ll miss the bus.
8 I’ll wait until you arrive.
9 Even though he was late, he finished his work.
10 Before we went to school, we ate breakfast.

Learn more: Complex Sentence

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