Grammar
Independent and Dependent Clauses
A related group of words with a subject and a predicate is called a clause.
A clause that makes sense by itself is an independent clause.
A clause that does not make sense by itself is a dependent clause.
Example: I had to wait in the office until my father arrived.
This sentence begins with an independent clause (I had to wait in the office) and ends with a dependent clause (until my father arrived).
If the dependent clause comes first, set it off with a comma: Until my father arrived, I had to wait in the office.
If the independent clause is first, no comma is needed: I had to wait in the office until my father arrived.