What Is a Compound Sentence?

What’s the Difference Between a Compound Sentence and a Complex Sentence?

As mentioned above, a compound sentence has at least two independent clauses. A complex sentence has one (and only one) independent clause and at least one dependent clause.

The sentence, “Ella got a new dog, and she’s going to bring it on Saturday” is a compound sentence because both “Ella got a new dog” and “she’s going to bring it on Saturday” are independent clauses. The sentence, “Before she went to the lake, Ella got a new dog,” is a complex sentence because “before she went to the lake” is a dependent clause, so that sentence only has one independent clause, not two.

Here are some examples of complex sentences.When the dependent clause occurs at the beginning of a sentence, it needs to be followed by a comma, but when the independent clause occurs at the beginning of a sentence, it isn’t followed by a comma.

“My brother was late because he forgot to feed the dog.” 

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  Even though “my brother was late” and “he forgot to feed the dog” are both independent clauses, this isn’t a compound sentence since “because,” the word that links them, isn’t a coordinating conjunction (it’s a subordinating conjunction). Therefore, “because” is included as part of the clause it’s in, and “because he forgot to feed the dog” is a dependent clause. Only coordinating conjunctions aren’t included in the clause they’re in when determining if a clause is independent or dependent.
  

 

“Whenever I hear his music, I start to cry.”   

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  “Whenever I hear his music” is the dependent clause  
  
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  "I start to cry" is the independent clause
  

 

“He has been very lonely since his best friend moved away.” 

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  “since his best friend moved away” is the dependent clause
  
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  "He has been very lonely" is the independent clause
  

 

What Is a Compound-Complex Sentence?

What happens when a sentence contains more than two clauses? If it has at least two independent clauses and at least one dependent clause, it becomes a compound-complex sentence.  (You might notice the compound-complex sentence requirements are just the requirements of a compound sentence and a complex sentence combined together).

Here are some compound-complex sentence examples. Note that each has at least two independent clauses and at least one dependent clause.

“I laughed when he fell in the mud, but then I felt sorry for him.”    

“Whenever we get coffee, she shows up late, and it’s really starting to bother me.” 

“The restaurant is so expensive; I’ll have to save up money before we can go.”