An adverb may be a single word such as quickly, here or yesterday , or a phrase such as the day before yesterday or to see my mother . Adverbs can also be clauses, containing a subject and a full verb.
Look at these sentences:
In the first sentence, "yesterday" is a one-word adverb, "on Friday" is an adverb phrase, and "before I left for Calgary" is a adverb clause. All of them answer the question "When?", but the adverb clause has a subject ("I") and a full verb ("left"). It is introduced by "before", so it is a dependent clause. This means that it cannot stand alone: "Before I left for Calgary" would not be a full sentence. It needs a main clause ("I saw the movie"). An adverb clause, then, is a dependent clause that does the same job as an adverb or an adverb phrase.
There are many types of adverb clauses. Here are some examples of the most common types:As you can see from the examples above, most adverb clauses can be recognized because they are introduced by a particular word or phrase (such as "when", "so that", etc.). These words and phrases are called subordinating conjunctions, and there are many of them, including the2e: