The first line of Doubt: A Parable is, What do you do when youre not sure? Playwright John Patrick Shanley spends the rest of the show not answering the question. Although its set in 1964, Doubtdiscusses issues that are hot buttons today. A hard-line nun accuses a liberal Catholic priest of sexually abusing a child. She doesnt have any proof, but that doesnt stop her. When the two square off, the people around them must choose sides. Maybe the priest is innocent. Maybe he isnt. Shanley, who won a Pulitzer Prize for the play, supplies enough information to support either viewpoint, but never answers the big questions. He leaves that to the audience. 8 p.m. Fridays and Saturdays. Through April 11. Company OnStage, 536 Westbury Square. For information, call 713-721-0243 or visit www.companyonstage.org. $13.