A、People with potential health problems. B、People over the age of 50. C、People who always stay up. D、People of long-term overwor

M: Dr. Helene of the National Sleep Foundation is here with us to talk about sleeping hours. Good morning, Dr. Helene. So first would you please to introduce the recent study findings to us?
W: OK. If you are getting a solid 8-hour-sleep or more at night, be aware, a new study says getting 8 hours maybe too much and also says that too much sleep could double your risk of an untimely death.
M: So I think this came as a shock because we’ve always heard 8 hours’ sleep is the ideal number. Now there’s a saying it’s 7.
W: Well, 7 is the great amount of sleep. We think the normal range is 7 - 9 hours, with increased risks of mortality with more than 9 hours’ sleep and fairly dramatic increase of heart disease and death with less than 5 hours.
M: Why will sleeping more than 9 hours or more be bad for your health?
W: You know that part of the information is thought to be possibly related with underlying diseases, so people who are already sick with something, whether they know it or not, may, in fact, need more sleep. But those of us who are only getting 5 hours are increasing the risk that may be changeable if we allocate 7.
M: That sounds bad and it sounds breakable. If you get the 5,you know, Sunday night and can you rest 2 or 3 hours as a nap on Monday to make up for what you lost?
W: Well, a nap will refresh you somewhat but an irregular pattern makes it hard to fall asleep, and 5 is where we see a double risk of heart disease and death, so we really want it be closer to 7 hour.
5.What can we learn about the latest study mentioned by the woman?
6.According to the woman, what kind of people possibly need more sleep?
7.What is the woman’s opinion towards nap?