Subordinate or Dependent Clauses can also be used as an adverb would be used in a sentence.  Remember that an adverb answers the questions: when, where, how, why, and to what extent or degree.  The whole dependent clause can also answer those questions.  When that dependent clause answers the questions: when, where, how, why, it will modify the verb in the independent clause.  When it answers to what extent or degree, it will codify either an adjective or an adverb in the independent clause.

Adverb clauses are introduced by:

•  Conjunctive Adverbs - when, whenever, where, wherever, while, before (not the preposition here, but an adverb), until, after, "as" and "since" in relation to time.
•  Subordinate Conjunctions - as, if, as though, because, that, so that, in order that, if, unless, though, although, than as (referring to manner or reason), since (referring to reason).

It is NOT important to identify the connective but it is important to know which word in the independent clause that is modified by the Adverb subordinate (or dependent) clause.

Examples...

When we approached very quietly, the "ghost" disappeared.

•  The adverb dependent clause is: when we approached very quietly.  It answers the question, when.  It therefore will modify the verb in the independent clause (disappeared).

Forecasters use very sensitive equipment so that they can make accurate observations.

•  The adverb clause is: so that they can make accurate observations.  It answers the question, why.  It modifies the verb in the independent clause: use.