... SINGULAR: the other book (is) the other (is) PLURAL: the other books (are) the others (are) Note that a final -s is used only for a plural pronoun (others) Another means one more in addition to the ... nothing at all: The building where they work is new The building in which they work is new The building, which they work in, is new The building that they work in is new The building they work ... incorrect: The person who they saw was sick (informal) The person whom they saw was sick (formal) There's the driver who the police arrested (informal) There's the driver whom the police arrested...