Independent clauses are groups of related words with a subject and a verb, that express a complete thought and, therefore, can stand alone as full sentences. The sentence provided consists of two clauses: a dependent one, which is <em>As he moved quickly up the field</em> and<em> an independent clause: Roberto was in a position to score</em> (this latter can stand alone as a full sentence: it expresses a complete thought).
If an analytical essay on expository text mentions that the test has too much _overstatement_, then the essayist might be saying that the author is stating his opinion too strongly.
