英语听力：自然百科 秋日黄石公园 Autumn—8
时间：2019-01-22 作者：英语课 分类：自然百科2012年
英语课
They may be a little safer here. But the food in the forest is far less nutritious 1 than on the riverbanks. If they want to eat well and avoid wolves this winter, they'll need to keep on moving. As the elk 2 move gradually downwards 3, they follow the rivers out of Yellowstone’s central plateau.
The rivers in turn follow the path of glaciers 4 that flowed from this great bowl in the last Ice Age, and carved their way right through the barrier of surrounding mountains. Today, these valleys are escape routes for animals from the returning ice of winter.
Lower down, the valleys broaden, the rivers slow, and a richer variety of trees grows in the alluvial 5 soils, the perfect home for Yellowstone’s most industrious 6 creature.
A beaver 7 can fell a cottonwood tree in just a few hours, hundreds in a year. The beaver doesn't chew through the whole trunk, just enough to make the tree unstable 8. It then retreats, and lets the wind do the rest.
adj.有营养的，营养价值高的
- Fresh vegetables are very nutritious.新鲜蔬菜富于营养。
- Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
n.麋鹿
- I was close enough to the elk to hear its labored breathing.我离那头麋鹿非常近，能听见它吃力的呼吸声。
- The refuge contains the largest wintering population of elk in the world.这座庇护所有着世界上数量最大的冬季麋鹿群。
adj./adv.向下的（地），下行的（地）
- He lay face downwards on his bed.他脸向下伏在床上。
- As the river flows downwards,it widens.这条河愈到下游愈宽。
冰河，冰川( glacier的名词复数 )
- Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
- It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）
adj.冲积的；淤积的
- Alluvial soils usually grow the best crops.淤积土壤通常能长出最好的庄稼。
- A usually triangular alluvial deposit at the mouth of a river.三角洲河口常见的三角形沉淀淤积地带。
adj.勤劳的，刻苦的，奋发的
- If the tiller is industrious,the farmland is productive.人勤地不懒。
- She was an industrious and willing worker.她是个勤劳肯干的员工。
n.海狸，河狸
- 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。