You Could Look It Up

Q. I would like to know if a rule exists for the use of “all” and “all of.” Which of these sentences is correct: All the employees submitted vacation requests OR All of the employees submitted vacation requests? Thanks for your help.

A. Chicago style deletes the “of” whenever possible; see CMOS 5.250, s.v. “all (of).” Dictionaries are great for figuring out what words mean. Look up “all” and you’ll learn that it can be used as an adjective modifying a subject (“all employees”) or as a pronoun subject, which can be modified by a prepositional phrase (“of the employees”). When you write “all the employees,” the latter construction is at work; the “of” is silent but understood.