Some clauses, however, cannot stand alone as sentences: in this case, they are dependent clauses or subordinate clauses. Consider the same clause preceded by the subordinating conjunction when:
Dependent clause
when the Prime Minister is in Ottawa
In this case, the clause cannot stand alone as a sentence since the conjunction when suggests that the clause is providing an explanation for something. As this dependent clause answers the question when? just like an adverb does, it is called a dependent adverb clause (or simply an adverb clause as adverb clauses are always dependent clauses). Note that this clause can replace the adverb tomorrow in the following example:
Adverb
The committee will meet tomorrow.
Adverb clause
The committee will meet when the Prime Minister is in Ottawa.
Dependent clauses may function as adverbs as well as nouns and adjectives.
