When to use a comma after "suddenly":
* When it introduces a dependent clause: If "suddenly" is followed by a clause that can't stand alone as a sentence (e.g., "Suddenly, the lights went out."), then you need a comma.
When to NOT use a comma after "suddenly":
* When it's part of a simple sentence: If "suddenly" is followed by a complete thought that can stand alone as a sentence (e.g., "Suddenly the lights went out."), then a comma isn't needed.
Examples:
* Comma needed: *Suddenly, the ground began to shake.* ("Suddenly" introduces the dependent clause "the ground began to shake.")
* Comma NOT needed: *Suddenly the lights went out.* ("Suddenly" is part of a complete sentence.)
Let me know if you have more examples you'd like help with!