Put a comma before the conjunction. The meeting was emotional , and Cindy drove home in a daze.
Dependent words show the relationship between a dependent clause and an independent one.
Use a comma when the dependent one comes first. She waited for the light to change while horns honked behind her. While horns honked behind her , she waited for the light. Transitional expressions show the relationship between ideas in separate independent clauses. Put a period or semicolon between the two dependent clauses, and put a comma after the transitional expression.