Try this: for a whole day, forget about the clock. Eat when you’re hungry and sleep when you’re tired. What do you think will happen?
You may be surprised to find that your day is much like most other days. You’ll probably get hungry when you normally eat and tired when you normally sleep. Even though you don’t know what time it is, your body does.
Inside our bodies are several clocklike systems that follow a 24- hour cycle. Everyone is unique, which is why you might like to stay up late while your sister always wants to go to bed early.
Regularly staying up late can make kids do worse on tests and quizzes. And working shifts at night leads to higher rates of heart disease.
“There is a growing sense that when we eat and when we sleep are important parts of how healthy we are,” says Steven Shea, Director of the Sleep Disorders Research Program at Brigham and Women’s Hospital in Boston.
“During the night, we are prepared to sleep,” Shea says. “During the day, we are prepared to eat and move around, If you reverse ( 颠倒) what you are doing, everything is out of phase. That can have adverse consequences.
What does the underlined sentence suggest?

A．We don’t need to care about time.

B．We don’t need the clock.

C．The clock is not useful.

D．The clock is not remembered.

What makes some like to stay up late while others go to bed early?

A．our bodies

B．our minds

C．the clock

D．our unique system

Steven Shea suggests ________.

A．when we eat, we are prepared to eat.

B．when we sleep, we are prepared to sleep

C．when we eat and when we sleep are important parts of how healthy we are

D．we are prepared to follow clocklike system

“Everything is out of phase.” means________.

A．everything is out of order

B．everything is bad

C．everything is good

D．everything is not controlled