Some well-meaning teachers do their pupils grave disservice by making them read a play when the students are about to see it in a theater. Do such teachers think plays on stage are better if you already know them? How contrary to a playwright's intentions! Or do such teachers believe students can't comprehend words spoien out loud, and might be confused with all that color and movement? Alas, poor student!
Don't deprive students (or anyone else) of theater's greatest pleasure: the delicious, often suspenseful thirst to know what comes next. Imagine seeing "The Merchant of Venice" not knowing in advance if Shylock will win or lose. And imagine a teacher (or textbook) undoing that pleasure. In our not knowing lies the play's adventure.
David Ball, "Backwards & Forwards" (page 33)