Michael is American high school student. Like many schoolmates, Michael used (eat) breakfast while it was still dark. But that changed when his high school followed a new time schedule two years ago.
The problem of school start time has become one of the most important issues are discussed in public. A growing number of sleep-related studies have pointed to high school students' need more sleep. More than half of the (child) between ages 15 and 17, as is shown by researches, sleep for 7 or (few) hours per night.
Children like to stay up at night, usually going to bed late and waking up late in the morning. These habits may (cause) by the biology (生理), according to researchers. They think changing the sleep schedule of children (be) unable to work, "Only going to bed earlier will not (certain) make someone less tired in the early morning hours, "said a researcher. He also added, "Kids' lack (缺乏) of enough sleep is a growing public health problem in our nation. We need to work out ways to deal with . Putting off school start time may be helpful."
