Below, a list of comma rules appears at left, and examples demonstrating these comma rules appear at right. Match the comma rule at left with its example at right.

	Use a comma before and, but or another coordinating conjunction linking main clauses (39a).
	Use a commas to set off most introductory elements (39b).
	Use a comma or commas to set off nonessential elements (39c).
	Use commas between items in a series (39d).
	Use commas between two or more adjectives that equally modify the same word (39e).
	Do not use a comma between subject and verb, verb and object, or preposition and object (39h.1).
	Do not use a comma in most compound constructions (39h.2).
	Do not use a comma after a conjunction (39h.3).
	Do not use a comma around essential elements (39h.4).
	Do not use a comma around a series (39h.5).

A.	Travelers, who decide to go at the last minute, can get some great deals.
B.	At the end of the era, "pop culture" emerged as the new defining term of all that is mainstream and hip.
C.	The governor, true to her word, declared a state of emergency well in advance of the impending storm in order to save lives.
D.	Global warming is a significant, urgent problem that cannot be ignored.
E.	Whole grains like, whole wheat flour, whole cornmeal, oatmeal, and brown rice, are great nutritional choices.
F.	Studies are, beginning to indicate a decline in the number of cases of lung cancer due to the success of smoking cessation programs.
G.	Those who consume a Mediterranean diet generally live longer , have much less heart disease , and appear to have better resistance to all diseases compared with people who eat a typical Western diet.
H.	The moon appears much larger, and brighter when it reaches its closest point in orbit to the Earth.
I.	The National Parks System includes famous parks like Yellowstone and, historic parks with old battlefields and giant lakes.
J.	Several studies show that making one's bed in the morning promotes better sleep at night, so it might also be argued that maintaining order in other rooms of a home also promotes better focus and clarity during the day.