A complex sentence is a type of sentence made up of an independent clause (a clause that expresses a complete thought) and a dependent or subordinate clause (a clause that can not stand alone as a sentence because it does not express a complete thought). In this type of sentence, the dependent clause is often introduced by a coordinating conjunction such as <em><u>when</u></em>(like in the sentence given), <em>after, while, because, since, if </em>and<em> until</em>, which also indicate the subordination of the clause to the independent clause.
The sentence given is structured like a complex sentence: It has a dependent clause, which it's <u><em>When Sara turned her homework in</em></u> and a dependent clause: <u><em>she forgot to put her name on it.</em></u>
The answer is number 4) a literary critic's analysis, because it is not written by a student and it is a reliable source compared to a blog, website, or student paper.
It is relative to how the professor teaches his subject. If he is passionat about his subject, it will reflect on the how the children learn. This said, the children learn from the knowledge of the professor and his experiences. The latter happens if the professor continusly engages with his students.
