Mastering Complex Sentences: Main and Subordinate Clauses

Every sentence you write carries a message, but not all sentences are created equal. Some stand alone with complete thoughts, while others need a partner to make sense. Understanding how main and subordinate clauses work together is the key to crafting sentences that are clear, sophisticated, and engaging.

What are main and subordinate clauses? 🔗

A main clause (also called an independent clause) is a group of words that can stand alone as a complete sentence. It contains a subject and a verb and expresses a complete thought. You can recognize a main clause because it makes sense on its own.

Consider these examples: “The dog barked.” “She finished her homework.” “They arrived late.” Each of these is a main clause because it delivers a complete idea.

A subordinate clause (also called a dependent clause), on the other hand, cannot stand alone as a complete sentence and relies on a main clause for meaning. Even though it contains a subject and a verb, it leaves readers hanging with an incomplete thought.

Look at these subordinate clauses: “when the alarm rang,” “because she studied hard,” or “if they leave now.” Each has a subject and verb, but none answers the question completely. When the alarm rang, what happened? Because she studied hard, what was the result? These clauses need to attach to a main clause to communicate a full idea.

How subordinate clauses connect to main clauses 🔗

Subordinate clauses attach to main clauses through specific connecting words. These fall into two main categories: subordinating conjunctions and relative pronouns.

Subordinating conjunctions 🔗

Common subordinating conjunctions include after, although, as, because, before, even if, even though, if, in order that, once, provided that, rather than, since, so that, than, though, unless, until, when, whenever, where, whereas, wherever, whether, while, and why. These words signal that the clause cannot stand alone.

For example: “Because it was raining, we stayed inside.” The subordinating conjunction “because” introduces the subordinate clause and links it to the main clause “we stayed inside.”

Relative pronouns 🔗

Relative pronouns include that, which, whichever, who, whoever, whom, whose, whosever, and whomever. These pronouns introduce subordinate clauses that describe or give more information about a noun.

For instance: “The book that you recommended was excellent.” Here, “that you recommended” is a subordinate clause modifying “book.”

Three types of subordinate clauses 🔗

Subordinate clauses serve different functions depending on what they modify or how they relate to the main clause.

Adjective clauses 🔗

An adjective clause modifies or describes a noun in the main clause and usually begins with relative pronouns such as who, whom, whose, which, or that. These clauses answer questions like “which one?” or “what kind?”

Example: “The student who scored highest received an award.” The clause “who scored highest” describes which student.

Adverb clauses 🔗

An adverb clause modifies a verb, adjective, or another adverb and explains how, when, where, and why something happens. These clauses typically start with subordinating conjunctions like because, if, when, or while.

Example: “She left early because she felt unwell.” The clause “because she felt unwell” explains why she left.

Noun clauses 🔗

A noun clause functions as a noun in the sentence. It can act as a subject, object, or complement. Noun clauses often begin with words like what, who, how, that, or whether.

Example: “What he said surprised everyone.” The entire clause “What he said” acts as the subject of the sentence.

Punctuation matters 🔗

Knowing where to place commas with subordinate clauses is essential for clear writing.

When the subordinate clause comes first 🔗

When you place a subordinate clause before the main clause, the clauses should be separated by a comma. This signals to readers that the main idea is coming next.

Example: “After she finished breakfast, she went for a walk.”

When the subordinate clause comes last 🔗

When you attach a subordinate clause at the end of a main clause, you will generally use no punctuation.

Example: “She went for a walk after she finished breakfast.”

Essential versus nonessential clauses 🔗

With adjective clauses, punctuation depends on whether the information is essential to the meaning. When the information in the clause clarifies a general noun, the clause is essential and requires no punctuation.

Example: “Students who submit late work may lose points.” The clause identifies which students, so no commas are needed.

However, when the clause provides extra information about a specific noun, it becomes nonessential and requires commas.

Example: “My brother, who lives in Boston, is visiting next week.” Since we already know which brother, the clause is additional information.

Why mastering clauses improves your communication 🔗

Understanding main and subordinate clauses transforms how you write and speak. Complex sentences communicate more detailed ideas and express the relationship between ideas more effectively than simple sentences alone.

Written communication benefits 🔗

In professional and academic writing, combining clauses helps you show the relationship among pieces of information and provides more content by demonstrating how ideas connect. Rather than writing choppy simple sentences, you create flow and demonstrate sophisticated thinking.

Consider the difference: “The project failed. The team lacked resources.” versus “The project failed because the team lacked resources.” The second version uses a subordinate clause to show cause and effect clearly.

Spoken communication benefits 🔗

In conversation, using subordinate clauses helps you express complex thoughts efficiently. You can qualify statements, explain reasoning, and add context without breaking your ideas into disconnected fragments.

For example, instead of saying “I can’t attend. I have another commitment. It’s at the same time,” you can say: “I can’t attend because I have another commitment at the same time.”

Practical exercises to build your skills 🔗

The best way to master clauses is through deliberate practice.

Identification exercise 🔗

Take any paragraph from a book or article and underline each main clause once and each subordinate clause twice. Notice how the writer combines them for effect.

Combination exercise 🔗

Start with simple sentences and combine them using subordinate clauses. For instance:

“The rain stopped. We went outside.” can become “After the rain stopped, we went outside.” or “We went outside after the rain stopped.”

Try different subordinating conjunctions to see how meaning shifts. “Although the rain stopped, we stayed inside” creates a different relationship than “because the rain stopped.”

Revision exercise 🔗

Review your own writing and look for strings of short, choppy sentences. See where you can combine ideas using subordinate clauses to create smoother, more sophisticated prose.

Common mistakes to avoid 🔗

Even experienced writers sometimes stumble with clauses. Watch out for these pitfalls.

Sentence fragments 🔗

A subordinate clause cannot stand alone as a sentence because the reader is left wondering what happened. Writing “Because she was tired.” as a complete sentence creates a fragment.

Comma errors 🔗

Forgetting the comma when a subordinate clause begins a sentence or adding unnecessary commas when it ends a sentence are frequent mistakes. Following the punctuation rules consistently prevents confusion.

Overusing complex sentences 🔗

While complex sentences add sophistication, too many in a row can make writing dense and difficult to follow. Varying sentence structure and length creates better flow and maintains reader engagement.

Putting it all together 🔗

Main and subordinate clauses are the building blocks of effective sentences. Main clauses deliver complete thoughts and can stand alone. Subordinate clauses add detail, explanation, and nuance but need to attach to main clauses through subordinating conjunctions or relative pronouns.

By understanding how these clauses function and how to punctuate them correctly, you gain control over your writing. You can emphasize important ideas, show relationships between thoughts, and create sentences that are both clear and engaging.

Practice identifying clauses in what you read. Experiment with combining ideas in your own writing. Pay attention to punctuation. Over time, using main and subordinate clauses effectively will become second nature, elevating both your written and spoken communication.

What do you think? Can you identify the main and subordinate clauses in the last paragraph you wrote? How might combining or separating clauses change the emphasis or clarity of your message?

References

1. https://www.grammarly.com/blog/grammar/subordinate-clause/
2. https://www.theenglishisland.com/lessons/subordinate-clauses/
3. https://chompchomp.com/terms/subordinateclause.htm
4. https://blog.udemy.com/example-of-a-complex-sentence/
5. https://courses.lumenlearning.com/suny-esc-communicationforprofessionals/chapter/sentence-structure/