M: What’s that orange thing on your computer screen?
W: It’s something I bought yesterday. It’s a plastic sheet that blocks blue light. I have one that I use to cover my phone screen too.
M: What do you mean by blue light?
W: Blue light includes natural light, but it also includes light that isn’t natural, for example, from computers, phones, televisions and other electronic devices.
M: So blue light is harmful and that’s why you want to block it.
W: It isn’t that simple. Blue light isn’t necessarily bad for us. In fact, we need blue light during the day to be healthy. But too much blue light, especially from electronic devices, can harm our health by weakening our vision and making it harder for us to fall asleep. And poor sleep can cause all sorts of health problems.
M: I’m not so sure that sleep is nearly as important as people always say it is. I haven’t slept enough in months because I have too much work to do, and I feel fine. And it’s the same for most of my friends. Poor sleep might be a problem for older people, but surely young people can handle late nights.

W: Well, the research I’ve read shows that sleep is probably even more important than we thought, and that not having enough sleep can contribute to serious health problems like obesity and heart disease. And all the artificial blue light from electronic devices means we have to try harder to sleep well.
M: Maybe you’re right. I’m on my computer very late most nights, and that’s probably why I don’t sleep enough.

Q8: What did the woman do to her computer?
Q9: What does the woman say about blue light?
Q10: Why does the man say he hasn’t slept enough for months?
Q11: What has the woman learned from the research she has read?