Trees are essential to beavers．They eat the bark on the upper branches，and in order to reach these they must fell the trees．Tree-felling is a skilled job，as anyone who has felled even a sapling knows． But beavers fell more than saplings．A pair is said to be able to fell a tree four inches in diameter in 15 minutes．They do it by gnawing all round the trunk，as high up from the ground as they can reach．They often build platforms of mud and earth to enable them to cut through the tree where the trunk is narrower．
The engineering skill of beavers is to a large extent a result of their ability to use their front paws as hands．A female will carry her young held under her chin with her front paws walking on her hind legs．A similar method is used by all beavers when transporting stones or mud，although they also carry such materials on their broad flat tails．The forepaws are also used for burrowing and for dragging heavier logs．
It is easy，therefore，to see why people should talk about the beaver’ s skill，cleverness and intelligence．However，the structure of the beaver’s brain gives no indication that the animal is any more intelligent than other rodents．Any of its actions，which appear to be the result of a higher order of reasoning，can be shown to be due to instinct and are suspected of being the outcome of an inborn pattern of behavior．
Questions 21-25 are based on Passage Five．
21．The passage implies that beavers prefer to build their home in_____.
A．deep water B．shallow water
C．rivers rather than pond D．1akes rather than rivers
22．The word “ elements ” in Paragraph 2 means_____.
A．natural habitations for animals
B．environment natural to an individual
C．atmospheric forces as rain, wind or snow
D．substances as earth, water, air and fire
23．The sentence “From an engineering point of view the lodge could hardly be improved ”means___．
A．the lodge was too poor to improve
B．the lodge was left much to improve
C．the lodge was nearly perfect
D．it is easy to improve the lodge
24．Beavers fell trees mainly to___．
A．build dams B．build their lodges
C．gain food D．exercise their jaws
25．Which of the following statements is best to describe beavers? |
