B
When you get really sleepy, you may nod off(打瞌睡) for a short time. Chinstrap penguins in the South Pole nod off more than 10,000 times a day!
A new study in Science says this. A group of scientists study 14 chinstrap penguins in the South Pole. They put electrodes(电极)on the penguins' heads and necks to see their brain activities(大脑活动). The scientists also follow them by the positioning system and watch them for ten days.
The penguins never have a long sleep—the longest sleep is 34 seconds. On average(平均),the penguins sleep 4
seconds at a time. But in one day,they sleep for more than 11 hours. So they get enough rest.
The penguins sleep like this because they need to protect their eggs and babies. If they sleep for too long, the babies may get hurt by seabirds and other penguins. Also, their home is usually noisy and crowded. So the parent penguins just have very short sleep to stay alert(警觉的).
()29. The first paragraph tells us that chinstrap penguins .
A. sleep mostly in the daytime
B. never get sleepy
C. often have short sleeps
D. need little sleep
()30. How long do the penguins usually spend on sleeping fifteen times?
A. Over an hour.
B. About ten minutes.
C. About one minute.
D. About thirty minutes.
()31. How do the penguins get enough sleep?
A. By sleeping for 34 seconds each time.
B. By having a long sleep every 11 hours.
C. By nodding off many times every day.
D. By having 11-hour-long sleep at a time every day.
()32. According to the last paragraph, what makes the penguins sleep like this?
a. They need to protect their eggs and babies.
b. The cold weather in the South Pole.
c. Not having a quiet and big home.
d. The living habits of seabirds.
A. ad B. ac
C. bc D. bd

29.C 30.C 31.C 32.B