【正确答案】 D

【答案解析】[解析] W: Hi, Jack. How is your economics paper going? M: It's coming along. But I've been staring at this computer screen for hours and my eyes hurt. W: Yeah. Doing that can make your eyes really dry and tired. You should take a break. M: I can't. I have to get this paper written. It's due tomorrow. W: You know I read about computers and eye problems recently. The article says that they are usually caused by not blinking your eyes enough. M: Blinking? I thought I just needed new glasses. W: No. When you blink, the movement of closing and opening your eyes, even though it happens really fast, helps moisten your eyes. It's the lack of moisture that causes the problem. M: That makes sense. But what does it have to do with the computer? W: People who use computers tend to stare at the monitor and blink less often than they normally would. That leads to dry, irritated eyes. M: Well, that's certainly how mine feel now. They really hurt. W: The article I read about the office workers found that the workers averaged 22 blinks a minute when relaxed. But just 7 a minute while looking at the text on a computer screen. M: Wow. That's quite a difference. W: They also kept their eyes open wider which means the moisture evaporated more quickly. M: I wonder if using some kind of eye-drops will make them feel better. W: That might help. But the best prescription is to take a break and rest your eyes. M: OK. Let's go get some coffee. I can finish this later tonight. What are the speakers mainly discussing?