Restrictive Clauses :


Clauses are also classified as restrictive and nonrestrictive clauses. (The words essential and nonessential are sometimes used and mean the same thing as restrictive and nonrestrictive, respectively. British grammarians will make this same distinction by referring to clauses with the terms defining and non-defining.) A nonrestrictive clause is not essential to the meaning of the sentence; it can be removed from the sentence without changing its basic meaning. Nonrestrictive clauses are often set apart from the rest of the sentence by a comma or a pair of commas (if it's in the middle of a sentence).

Professor Villa, who used to be a secretary for the President, can type 132 words a minute.