We introduce a novel approach for automatically generating a virtual instructor from textual input only. Our fully implemented system first analyzes the rhetorical structure of the input text and then creates various question-answer pairs using patterns. These patterns have been derived from correlations found between rhetorical structure of monologue texts and question-answer pairs in the corresponding dialogues. A selection of the candidate pairs is verbalized into a diverse collection of question-answer pairs. Finally the system compiles the collection of question-answer pairs into scripts for a virtual instructor. Our end-to-end system presents questions in pre-fixed order and the agent answers them. Our system was evaluated with a group of twenty-four subjects. The evaluation was conducted using three informed consent documents of clinical trials from the domain of colon cancer. Each of the documents was explained by a virtual instructor using 1) text, 2) text and agent monologue, and 3) text and agent performing question-answering. Results show that an agent explaining an informed consent document did not provide significantly better comprehension scores, but did score higher on satisfaction, compared to two control conditions.