In order to make sure students are keeping up with the readings (and to encourage students to come to class!) I give quite a few surprise quizzes during the semester.  Often, these surprise quizzes involve short essays on the reading assigned for that day.  Very frequently, I use one of the "primary source" study questions as the surprise quiz question.  If you keep up with the readings, and  (especially) if you are prepared to answer the study guide questions, you should do well on these quizzes.