Time in the Animal World
Rhythm controls everything in Nature. ____1____
The sun provides a basic time rhythm for all living creatures including humans. Nearly all animals are influenced by sun cycles and have developed a biological clock in their bodies following these cycles. The moon also exerts its force and influence on the sea. Its gravitational attxacSon causes the rising of the tide. ____2____When the moon is behind the Earth, centrifugal force causes the second tide of the day.
Animals living in tidal areas must have the instinct of predicting these changes, to avoid being stranded and dying of dehydration. Since the time of the dinosaurs, the king crab has been laying eggs1 at the seaside in a set way2. To avoid predator fish3，the eggs are always far from seawater and protected by sand. In the following two months, the eggs undergo dramatic changes related to the cycles of the moon4. When the second spring tide comes, the young king crabs have matured. ____3____
Most of the mammals, either the giant elephant or the small shrew, have the same average total number of heartbeats in their lifetime. Shrews live only for two and a half years, and spend their life at a high speed and high tempo. Animals like shrews with a pulse rate of 600 per minute have an average total of eight hundred million heartbeats5 throughout their life. The African elephant has a pulse rate of 25 beats per minute, and a life span6 of 60 years. The size of the body determines the speed of life. ____4____
As we get older, our sense of time is being influenced by the physiological changes of our body. The elderly spend more time resting, and do few sports. ____5____ For a child, a week is seen as a long time.
练习：
A For an adult, time goes fast year by year.
B It controls, for example, the flapping of birds, wings, the beating of the heart and the rising and setting of the sun.
C The larger the animal is, the longer its life span is and the slower its life tempo is.
D The tide goes out when the moon moves away and its attraction is weaker.
E We always tend to think all the animals have the same sense of time as human beings.
F The second spring tide takes them back to the sea.
答案与题解：
1.B “空1”前面的句子“Rhythm controls everything in Nature”是主题句。“空1”的句子应该是陈述主题句的细节。选项B的“It controls, for example, the flapping of birds’ wings, the beating of the heart and the rising and setting of the sun”是主题句的例解。controls是两个句子的词汇连接手段，两个句子的内容也连贯，所以B是答案。
2.D “空2”前面两句说，月亮对大海施加力量和影响，其地心吸力造成涨潮。“空2”后的句子涉及第二次涨潮。可以推断，位于这两个句子之间的“空2”的内容应该与大海和潮汐有关。选项D说的是退潮，因此是答案。
3.F 第三段说到生长在潮汐地区的动物具有预测潮汐的本能。然后举king crab为例。鲎远离海岸产卵，并将之埋在沙下，防止食肉鱼吞食。到第二次春潮来临时,小鲎已破壳而出。“空3”应该填什么呢?选项F出现second spring，这是与上一句联系的信号。再看内容，它是上一句意思的自然发展，所以F是答案。
4.C 第四段说到哺乳动物不管寿命长短、体形大小，其一生心跳总次数大致相同。作者以体形大、寿命长的大象和体形小、寿命短的shrew(鼩鼱)为例说明。本段倒数第二句是结论：The size of the body determines the speed of life。“空4”应该填什么呢?估计应该与上述结论有关。选项C的“The larger the animal is, the longer its life span is and the slower its life tempo is”是对上一句的结论的细化说明，所以C是答案。
5.A 第五段说到随着年龄的增长，生理变化会影响人的时间感。“空5”前面一句说到老人，“空5”后面一句说到小孩。由此可以判断，“空5”的内容会涉及另一个年龄段。选项A说了一个成年段，所以A是答案。
