Question

The following sentence contains _____.

Our old automobile, driven 100,000 miles, was sold to a junk dealer.

one main clause
two main clauses
one main and one subordinate clause
one main and two subordinate clauses

Answer 1

One main and one subordinate clause. 

Answer 2

The correct answer is one main clause.
This means that there is only one verb in the sentence, which in this case is the verb 'was.' Even though drive is also a verb, in this context it is used as an adjective driven (participle form of the verb to drive) and is thus not considered to be a verb. This means that there are no subordinate clauses but rather just one main clause.