Do you jump out of bed early，wide awake and ready to start your day？If so，you would be considered an"early bird"．Perhaps，though，you hate the sound of your alarm clock each morning and have little energy until afternoon．If that's the case，you're probably a"night owl"．
Most of us fall into one of these two groups，but what makes us this way？And is one better than the other？There are different opinions．
Traditionally，early risers have been praised as hardworking．On the other hand，those who prefer to sleep in and get up late are considered lazy．But even in the 21st century， most people still believe the early bird catches the worm．
Yet some scientists now believe"night owls"can really focus 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 10hours of being awake，the"evening people"became more alert．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 of energy 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) How does the author introduce the subject？ ______

A. By asking questions．

B. By showing research results．

C. By telling a story．

D. By describing two different lifestyle．

(2) What does the underlined sentence in Paragraph 3 really mean？ ______

A. "Night owls"can focus longer than"early birds"．

B. "Night owls"are as hardworking as"early birds"．

C. Early risers have an advantage over late risers．

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

(3) What did the researchers find in a Belgian study？ ______

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

B. Late risers can think quickly after being awake for 10hours．

C. Early risers become as focused as later risers．

D. Late risers become sleepier than early risers．

(4) According to the passage，which of the following has the most influence on one's sleep habits？ ______

A. Genetic elements．	B. Lifestyle and activities．
C. Living environment．	D. Childhood routines．