How does a playwright reveal character in just one line? That's a very important asset for a playwright. Here's an example of how Jean Kerr does it. The character in question is the heroine's ex-husband's new girlfriend. We are to understand that she's not right for her fiance, who would be much better off going back to his wife. So, upon being offered a cigarette, she responds in the negative, but says: "Not because I'm worried about cancer, but they stain your teeth!" Subtle, no? ( )