COMPLEX SENTENCES
Definition
A complex sentence contains exactly one independent clause and one or more dependent (subordinate) clauses. A dependent clause has a subject and a verb, but it cannot stand alone as a sentence — it depends on the independent clause to complete its meaning. Dependent clauses are introduced by subordinating conjunctions (because, although, when, if, since, after, before, while, unless, until, even though, as soon as, etc.) or relative pronouns (who, which, that, whose, whom).
Structures:
[Independent Clause] + [Subordinating Conjunction + Dependent Clause]
[Subordinating Conjunction + Dependent Clause], + [Independent Clause]
Key Rules
✔ Rule: The independent clause can stand alone; the dependent clause cannot.
✔ Rule: When the dependent clause comes FIRST (before the independent clause), use a comma after the dependent clause.
✔ Rule: When the dependent clause comes SECOND (after the independent clause), no comma is typically needed.
✔ Rule: Subordinating conjunctions always introduce dependent clauses and show a relationship: time, cause/effect, condition, concession, contrast, or purpose.
✔ Rule: Relative clauses (introduced by who, which, that) are also dependent clauses and make a sentence complex.
Common Subordinating Conjunctions by Function:
Time: when, while, after, before, until, as soon as, since
Cause/Effect: because, since, as
Condition: if, unless, provided that, as long as
Contrast/Concession: although, even though, while, whereas, though
Purpose: so that, in order that
10 Examples of Complex Sentences
1. Although it was raining heavily, the outdoor concert continued without pause. [Dependent clause first → comma after it]
2. She left the party early because she had an important meeting the next morning. [Dependent clause second → no comma]
3. If you study consistently every day, you will see great improvement in your English. [Condition → dependent clause first]
4. The professor who teaches American history is also an award-winning author. [Relative clause with ‘who’]
5. While the children played in the yard, their parents prepared a barbecue. [Time relationship]
6. He didn’t answer the phone even though he was sitting right next to it. [Concession/contrast]
7. As soon as the flight landed, she turned her phone back on to check her messages. [Time: as soon as]
8. Unless you leave now, you will miss the last train to downtown Chicago. [Condition with ‘unless’]
9. The package that arrived yesterday was damaged during shipping. [Relative clause with ‘that’]
10. Since he moved to New York three years ago, he has tried dozens of new restaurants. [Time/cause with ‘since’]
📌 Note: ‘Because I was tired’ is a FRAGMENT — it is a dependent clause that cannot stand alone. Add an independent clause: ‘I went to bed early because I was tired.’ Now it is a complete complex sentence.
Extended Dialogue: Complex Sentences in Action
Context: Two friends — Mia and Carlos — are catching up after not seeing each other for a while. Notice the dependent clauses (underlined in the labels) and how they relate to the main clause.
Mia: I’ve been so busy since I started that new job downtown!
→ Independent: I’ve been so busy | Dependent: since I started that new job downtown
Carlos: I noticed! You look exhausted, even though you seem really happy.
→ Independent: you seem really happy | Dependent: even though you look exhausted
Mia: I am happy! Although the hours are long, the work is incredibly rewarding.
→ Dependent first: Although the hours are long, → comma → Independent clause
Carlos: That’s what matters most. What do you actually do there?
→ Simple + question
Mia: I manage a team that develops mobile apps for small businesses.
→ Relative clause: that develops mobile apps for small businesses
Carlos: Wow! When did you get into app development?
→ Complex question: dependent clause introduced by ‘when’
Mia: I started learning to code after I finished my business degree.
→ Dependent: after I finished my business degree
Carlos: That’s impressive. I might try it, too, if I can find a good online course.
→ Dependent: if I can find a good online course (conditional)
Mia: You absolutely should! As long as you stay consistent, you’ll pick it up pretty quickly.
→ Dependent first: As long as you stay consistent, → comma → Independent
Carlos: I’ll start researching courses tonight because I want to make a career change by next year.
→ Dependent: because I want to make a career change by next year (cause)
Mia: Send me what you find so that I can give you my recommendations.
→ Dependent: so that I can give you my recommendations (purpose)
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