阅读理解（六）
1、Getting less sleep has become a bad habit for most American kids. According to a new survey(调查)by the National Sleep Foundation, 51% of kids aged 10 to 18 go to bed at 10 pm or later on school nights, even though they have to get up early. Last year the Foundation reported that nearly 60% of 7- to 12-year-olds said they felt tired during the day, and 15% said they had fallen asleep at school.
How much sleep you need depends a lot on your age. Babies need a lot of rest; most of them sleep about 18 hours a day! Adults need about eight hours. For most school-age children, ten hours is ideal(理想的). But the new National Sleep Foundation survey found that 35% of 10- to 12-year-olds get only seven or eight hours. And guess what almost half of the surveyed kids said they do before bedtime? Watch TV.
"More children are going to bed with TVs on, and there are more opportunities(机会)to stay awake, with more homework, the Internet and the phone," says Dr. Mary Carskadon, a sleep researcher at Brown University Medical School. She says these activities at bedtime can get kids all excited and make it hard for them to calm down and sleep. Other experts say part of the problem is chemical. Changing levels of body chemicals called hormones not only make
te enagers’ bodies develop adult characteristics, but also make it hard for teenagers to fall asleep before 11 pm.
Because sleepiness is such a problem for teenagers, some school districts have decided to start high school classes later than they used to. Three years ago, schools in Edina, Minnesota, changed the start time from 7:25 am to 8:30 am. Students, parents and teachers are pleased with the results.
1.What is the new National Sleep Foundation survey on?
A.American kids' sleeping habits.
B.Teenagers' sleep-related diseases.
C.Activities to prevent sleeplessness.
D.Learning problems and lack of sleep.
2.How many hours of sleep do 11-year-olds need every day?
A.7 hours.
B.8 hours.
C.10 hours.
D.18 hours.
3.Why do teenagers go to sleep late according to Carskadon?
A.They are affected by certain body chemicals.
B.They tend to do things that excite them.
C.They follow their parents' examples.
D.They don't need to go to school early.
2、Steven Stein likes to follow garbage trucks. His strange habit makes sense when you consider that he’s an environmental scientist who studies how to reduce litter, including things that fall off garbage trucks as they drive down the road. What is even more interesting is that one of Stein's jobs is defending an industry behind the plastic shopping bag.
Americans use more than 100 billion thin film plastic bags every year. So many end up in tree branches or along highways that a growing number of cities do not allow them at checkouts(收银台) . The bags are prohibited in some 90 cities in California, including Los Angeles. Eyeing these headwinds, plastic-bag makers are hiring scientists like Stein to make the case that their products are not as bad for the planet as most people assume.
Among the bag makers' argument: many cities with bans still allow shoppers to purchase paper bags, which are easily recycled but require more energy to produce and transport. And while plastic bags may be ugly to look at, they represent a small percentage of all garbage on the ground today.
The industry has also taken aim at the product that has appeared as its replacement: reusable shopping bags. The stronger a reusable bag is, the longer its life and the more plastic-bag use it cancels out. However, longer-lasting reusable bags often require more energy to make. One study found that a cotton bag must be used at least 131 times to be better for the planet than plastic.
Environmentalists don't dispute(质疑) these points. They hope paper bags will be banned someday too and want shoppers to use the same reusable bags for years.
1.What has Steven Stein been hired to do?
A.Help increase grocery sales.
B.Recycle the waste material.
