Some Definitions

• Clause: a group of words containing a subject and a predicate
• Independent (Main) Clause: a clause that can stand alone as a sentence
  • I lost my hat.
• Coordinating Conjunction: a word that joins two independent clauses
  • and, as, but, for, nor, or, so, yet
• Dependent (Subordinate) Clause: a clause that cannot stand alone as a sentence because it contains a subordinating conjunction
  • before I put my keys away
• Subordinating Conjunction: a word that appears at the beginning of a dependent clause and makes the clause unable to stand alone as a sentence
  • although, because, since, if, whenever
    

Three Basic Sentence Structures and Their Punctuation

1. Simple Sentence

   Independent clause.

• The umbrella is in the car.
  
2. Compound Sentence
   

   Independent clause, coordinating conjunction independent clause.
   

• It has begun raining since we arrived, and the umbrella is in the car.
  

Note that the coordinating conjunction in a compound sentence is preceded by a comma.


3. Complex Sentence
   

   Independent clause dependent clause.
   

   • It wouldn’t have started raining if I hadn’t left the umbrella in the car.
     

   Dependent clause, independent clause.
   

   • If I hadn’t left the umbrella in the car, it wouldn’t have started raining.
     

   Note that in a complex sentence, if the dependent clause precedes the independent clause, the two clauses are separated by a comma. However, if the independent clause comes first, no comma is necessary.
   

    

   Note: Sentences that combine compound and complex structures (compound-complex sentences) incorporate the punctuation appropriate to the type of conjunction.
   

Click on the links below for more writing tips:

 

Critical Thinking

Punctuation Pointers: Colons & Semicolons

Punctuation Pointers: Apostrophes & Quotation Marks

Writing Tips