Comma

a.    Use when listing items in text, when separating clauses, or when it is necessary to express a short pause in a sentence.

b.    Use pairs of commas (or dashes) in mid-sentence, if desired, in place of parentheses/round brackets.

c.    Use between the last two items in a list of three or more items to minimize misreading. (Known as the serial comma, Harvard comma, or Oxford comma.) Watch out for mismatched items, which can create confusion even with the serial comma.

e.g. In her travels she went to Yokohama, Kyoto, and Nara.

d.    Use after the date in US-style dates.

e.g. March 21, 1970.

e.    Use to separate a direct quotation from the rest of the sentence by commas between the words and the quotation marks prior to the quotation, and at the end of the quotation (within quotation marks).

e.g. “Meet me at the station,” she ordered.  He shouted back, “I’m not going to meet you anywhere.”

Exceptions: Do not set off with commas if a quotation is

• woven into the syntax of a sentence, 

e.g. If you don’t watch for non-verbal cues, you won’t recognize when a spoken “Yes” means “No.”

• or the entire quotation is used as though it were a noun,

e.g. Carey had high expectations for his missionary career, adopting “expect great things of God, attempt great things for God” as his motto.

f.    Use for numbers greater than 999, but with no spaces within the number.

e.g. 1,200 and 1,200,000.

g.    If already in use, use semicolons to separate items.

e.g. In her travels she visited Japanese castles in Tokyo, Kyoto, and Nara; she ate sushi in Sendai; and skied in Hokkaido.

h.    Unnecessary after e.g., but used before e.g. if in running text.

e.g. She liked most Japanese food, e.g. sushi and noodles.

i.    Commas are unnecessary before etc. unless the sentence might otherwise be misconstrued.

j. Positioning of commas with respect to closing quotation marks.

(AmE) Periods are always placed inside quotation marks (even if a quotation is only a portion of the sentence).

e.g. The dog barked, “Woof, woof.”

e.g. The survey response said, “We always look forward to getting Japan Harvest in our mailbox.”

(BrE) Full stops are placed outside inverted commas unless a quotation stands by itself as a full sentence.

e.g. The dog barked, “Woof, woof”.

e.g. The survey response stated, “We always look forward to getting Japan Harvest in the post.”