Commas are often used to separate clauses. In English, a comma is used to separate a dependent clause from the independent clause if the dependent clause comes first: "After I fed the cat, I brushed my clothes." (Compare this with "I brushed my clothes after I fed the cat.") A relative clause takes commas if it is non-restrictive, as in "I cut down all the trees, which were over six feet tall." (Without the comma, this would mean that only the trees more than six feet tall were cut down.) Some style guides prescribe that two independent clauses joined by a coordinating conjunction ("for", "and", "nor", "but", "or", "yet", "so") must be separated by a comma placed before the conjunction. In the following sentences, where the second clause is independent (because it can stand alone as a sentence), the comma is considered by those guides to be necessary: