Subordinate Clause. It is called a subordinate clause because it plays a subordinate role in relation to the main clause within a sentence. It must be used with a main clause.
It needs to be connected to an independent clause in order to make sense. Like all clauses it will have both a subject and a verb. A subordinate or dependent clause cannot stand alone as a sentence because it as an alone part cannot express complete meaning or sense.
It will instead make a reader want additional information to finish the thought.
Adverbial subordinate clauses modify or give information about the verb in the main clause. That is made with soy instead of milk and cream. When whenever since until before after while as by the time as soon as. A subordinate clause or dependent clause is a clause that cant exist as a sentence on its own.