For whom does the bell toll? For him Who rings the bell? He rings the bell 12.4 That vs which As we saw in the comma example. there are two kinds of relative clauses restrictive clauses, which limit who or what is being talked about, and non- restrictive clauses, which merely add further information to something that has already been identified Nonrestrictive clauses begin with who(m) or which, but not that. They are set off by commas. Thus onald Reagan, who was our oldest President, is a Republican. Blairs Theorem, which is also known as Murphy's Law, states that Restrictive clauses begin with who(m)or that. Some grammarians say that a restrictive clause cannot begin with which; others allow it. Thus a man who used to be an actor became president The theorem that [which? I want to prove is 12.5 Possessives Possessives of nouns, singular or plural, are formed by the following sure-fire procedure: 1. Add an apostrophe 2. If an s is not already present, add it singular boy, possessive boy's plural boys, possessive boysFor whom does the bell toll? For him. Who rings the bell? He rings the bell. 12.4 That vs. which As we saw in the comma example, there are two kinds of relative clauses: restrictive clauses, which limit who or what is being talked about, and non￾restrictive clauses, which merely add further information to something that has already been identified. Nonrestrictive clauses begin with who(m) or which, but not that. They are set off by commas. Thus: Ronald Reagan, who was our oldest President, is a Republican. Blair’s Theorem, which is also known as Murphy’s Law, states that. . . Restrictive clauses begin with who(m) or that. Some grammarians say that a restrictive clause cannot begin with which; others allow it. Thus: A man who used to be an actor became President. The theorem that [which?] I want to prove is. . . 12.5 Possessives Possessives of nouns, singular or plural, are formed by the following sure-fire procedure: 1. Add an apostrophe. 2. If an s is not already present, add it. Thus: singular boy, possessive boy’s plural boys, possessive boys’ 12