题目内容：

Do you jump out of bed early, wide awake and ready to start your day？If so, you would be called an “early bird”. Perhaps, you hate the sound of your alarm clock（闹钟） each morning and have little energy until afternoon. If so, you're probably a “night owl”．

Most people can be divided into such two groups, but what makes us this way？And is one better than the other？There are different opinions.

Usually, early risers have been praised as hard-working while those who prefer to get up late are considered lazy. Most people believe the early bird catches the worm.

Yet some scientists now believe “night owls” can really focus(集中) longer and produce more than early risers.

Research has found that the early bird does not always get the worm. In a Belgian study, both “morning people” and “evening people” were watched during their normal asleep and awake routines(常规)．After 10 hours of being awake, the “evening people” became more alert(思维敏捷的). However, the “morning people” became sleepy and less focused. Researchers believe the reason for this difference is that night owls receive a last-minute increase from their brains. This added energy allows them to stay alert for longer periods of time.

Environment, lifestyle, activities and childhood routines all may have an effect on sleeping habits, yet genetics(遗传学)may play the biggest role.

It is possible to change your sleeping habits through regular bedtimes, early exercise and by avoiding midnight snacks. But if you're happy rising early or staying up late, you're probably doing what works best for your own personal body clock.

1.The author introduces the subject by ________.

A. telling an interesting story

B. giving different opinions

C. showing research results

D. asking a question

2.What does the underlined sentence in Paragraph 3 really mean?

A. Those who get up early achieve their goals.

B. Early to bed, early to rise is good for health.

C. “Night owls” can focus longer than “early birds”.

D. “Early birds” are as hard-working as “night owls”.

3.What did the researchers find in a Belgian study?

A. Late risers become sleepier than early risers.

B. Early risers become as focused as later risers.

C. Late risers can think quickly after being awaken for 10 hours.

D. Early risers can think clearly after being awake for 10 hours.

4.What opinion does the author finally agree to?

A. People should get up early.

B. Whatever time suits you, it’s OK.

C. Staying up late is good for health.

D. It’s impossible to change one’s sleeping habit.