【英语时差8,16】山楂树如何帮助构建生态平衡2

 To understand why a plant would grow such heavy thorns, we need to look back ten or fifteen thousand years to a time when mastodons, mammoths, ground sloths¹, tapirs, and peccaries browsed² from trees and bushes all over North America. Unlike today’s smaller herbivores, these animals would have had trouble getting through the big thorns. So the thorns helped create an ecological³ balance between the plants and a large group of voracious⁴ herbivores. Some of the other plants whose thorns evolved in response to ancient herbivores include wild plums, wild crab⁵ apples, honey locust⁶ and black locust. Most of these large herbivores became extinct about ten thousand years ago but the thorns that we see on plants today are living reminders⁷ of a whole range of animals that we now know only in fossil form.

1 sloths   

懒散( sloth的名词复数 )； 懒惰； 树獭； （经济）停滞。

参考例句：

• Mummies of pleistocene ground sloths, with original skin, hair, tendons and claws have been found. 还发现了保存原有皮肤，毛发，腱和爪的更新世时期地面树懒的木乃伊。
• He was inspired by fossils of armadillos and sloths. 犰狳和树懒化石让他获得了灵感。

2 browsed   

v.吃草( browse的过去式和过去分词 )；随意翻阅；（在商店里）随便看看；（在计算机上）浏览信息

参考例句：

• I browsed through some magazines while I waited. 我边等边浏览几本杂志。 来自辞典例句
• I browsed through the book, looking at page after page. 我翻开了一下全书，一页又一页。 来自互联网

3 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

4 voracious   

adj.狼吞虎咽的，贪婪的

参考例句：

• She's a voracious reader of all kinds of love stories.什么样的爱情故事她都百看不厌。
• Joseph Smith was a voracious book collector.约瑟夫·史密斯是个如饥似渴的藏书家。

5 crab   

n.螃蟹，偏航，脾气乖戾的人，酸苹果；vi.捕蟹，偏航，发牢骚；vt.使偏航，发脾气

参考例句：

• I can't remember when I last had crab.我不记得上次吃蟹是什么时候了。
• The skin on my face felt as hard as a crab's back.我脸上的皮仿佛僵硬了，就象螃蟹的壳似的。

6 locust   

n.蝗虫；洋槐，刺槐

参考例句：

• A locust is a kind of destructive insect.蝗虫是一种害虫。
• This illustration shows a vertical section through the locust.本图所示为蝗虫的纵剖面。

7 reminders   

n.令人回忆起…的东西( reminder的名词复数 )；提醒…的东西；（告知该做某事的）通知单；提示信

参考例句：

• The film evokes chilling reminders of the war. 这部电影使人们回忆起战争的可怕场景。
• The strike has delayed the mailing of tax reminders. 罢工耽搁了催税单的投寄。