14. Between two clauses, one of which depends on the other, and usually introduced by if, when, unless, though, where, wherever, etc.: e.g., If we stand together, success is assured. If the clauses are closely connected both in sense and construction, the comma is not required: e.g., William was ten years old when his father moved to Boston.
15. In compound sentences, to separate the co-ordinate clause when closely related and simple in construction: e.g., He was {7} courteous, not cringing, to superiors; affable, not familiar, to equals; and kind, but not condescending, to inferiors.
16. To indicate an ellipsis: e.g., Price, seventy-five cents.
17. To separate vocative words or expressions from the context: e.g., I leave it, gentlemen, to your sense of right and wrong.
18. Before not, when introducing an antithetical clause: e.g., He devoted his attention to the matter before him, not because he was interested, but because he could not avoid the issue.
19. To separate similar or identical words, even though not required by the sense or grammatical construction: e.g., I tell you, you are wrong.
20. To separate two numbers: e.g., March 1, 1912; In 1911, 869 cases were reported.
21. To separate a quotation or similar brief expression from the preceding part of the sentence: e.g., To quote the proverb, “Look before you leap.”
22. Before the word of, connecting a proper name with residence or position: e.g., Senator Lodge, of Massachusetts.
23. After the salutatory phrase at the beginning of a letter, when informal: e.g., My dear Mother, but, when formal, Gentlemen: