英语听力：自然百科 秋日黄石公园 Autumn—9

 It cuts branches into more manageable lengths and then swims them down a network of purpose-built canals towards the dam. 

 

The pond to give this beaver¹ protection from predators², and the canals allow it to forage³ far into the forest, carrying many times its own weight with ease. 

 

Autumn is the busiest time of year for beavers⁴. It won’t be so easy to make repairs when the pond is frozen over.

 

The sound of running water is their stimulus⁵ to shore up gaps with timber and plug leaks with mud. 

 

But the dam not only serves the beavers. Moose come here from the forests around to feed on weeds that thrive in the beaver’s shallow pond. The weed is rich in vital sodium⁶ that the forest can’t easily provide.

 

But now that winter is approaching，another essential role for the dam is revealed. These smaller branches are not for fixing the dam, they are for eating.

 

The beaver secures them to the mud in the late autumn.

1 beaver   

n.海狸，河狸

参考例句：

• The hat is made of beaver.这顶帽子是海狸毛皮制的。
• A beaver is an animals with big front teeth.海狸是一种长着大门牙的动物。

2 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

3 forage   

n.(牛马的)饲料，粮草；v.搜寻，翻寻

参考例句：

• They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
• Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。

4 beavers   

海狸( beaver的名词复数 )； 海狸皮毛； 棕灰色； 拼命工作的人

参考例句：

• In 1928 some porpoises were photographed working like beavers to push ashore a waterlogged mattress. 1928年有人把这些海豚象海狸那样把一床浸泡了水的褥垫推上岸时的情景拍摄了下来。
• Thus do the beavers, thus do the bees, thus do men. 海狸是这样做的，蜜蜂是这样做的，人也是这样做的。

5 stimulus   

n.刺激，刺激物，促进因素，引起兴奋的事物

参考例句：

• Regard each failure as a stimulus to further efforts.把每次失利看成对进一步努力的激励。
• Light is a stimulus to growth in plants.光是促进植物生长的一个因素。

6 sodium   

n.（化）钠

参考例句：

• Out over the town the sodium lights were lit.在外面，全城的钠光灯都亮了。
• Common salt is a compound of sodium and chlorine.食盐是钠和氯的复合物。