It is easy to spot a subordinate clause in a sentence because a subordinate clause begins with a subordinate conjunction or a relative pronoun.
Relative pronouns are that, which, whichever, who, whoever, whom, whomever, whose.
Here are some subordinate conjunctions:
after, although, as, because, before, even if, even though, if, in order that, once, provided that, rather than, since, so that, than, that, though, unless, until, when, whenever, where, whereas, wherever, whether, while, why.
