Use commas to set off nonrestrictive elements. The bus drivers , rejecting the management offer, remained on strike. Use commas to separate items in a series. The long, twisting, muddy road led to a shack in the woods. Use commas to separate parenthetical expressions.
Parenthetical expressions are added comments or information.
Use commas with dates, addresses, titles, and numbers. Canton, Ohio is more interesting than Des Moines, Iowa. Martin Luther King, Jr., was a great civil rights leader. Use commas with quotations. Use commas to facilitate understanding.