Comma Usage – Dependent and Independent Clauses Joined by Coordinating Conjunctions

1. Use a comma to separate two independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, or, for, nor, so, yet.

2. DO NOT use a comma to separate a compound predicate (verb), a sentence with one subject and two verbs.

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All of the following are correct. Can you spot and explain the differences?

• I went home at 9 p.m. last night. I immediately fell asleep.
• I went home at 9 p.m. last night, and I immediately fell asleep.
• I went home at 9 p.m. last night and immediately fell asleep.

Answers:

• I went home at 9 p.m. last night. I immediately fell asleep.
  • These are two complete sentences.
• I went home at 9 p.m. last night, and I immediately fell asleep.
  • This is an example of two independent clauses joined by a coordinating conjunction, FANBOYS.
    • What is an independent clause?
      • An independent clause can stand on its own as a complete sentence.
      • Do you remember the rules for a complete sentence?
        • An independent clause or complete sentence must have the following:
          1. Verb
          2. Subject
          3. Complete idea
• I went home at 9 p.m. last night and immediately fell asleep.
  • This example sentence has one subject, “I”, and two verbs, “went” and “fell asleep”:
    1. “I went home last night”
    2. “immediately fell asleep.”
  • DO NOT use a comma to separate the coordinating conjunction for sentences with a compound predicate (verb), a sentence with one subject and two verbs.

Examples:

• The game was over, and we went home.
• The game was over, but the crowd refused to leave.
• The student explained her question, yet the instructor still didn’t seem to understand.
• Yesterday was her brother’s birthday, so we had a surprise birthday party for him.

Notice the following:

• My grandfather is old. He has the wisdom (지혜) that comes with age.
• My grandfather is old and has the wisdom that comes with age.
• My grandfather is old, and he has the wisdom that comes with age.