英语听力：自然百科 黄石公园的夏天 Yellowstone—6

 As the migrating herds¹ arrive in the plateau’s river valleys, the spring is here.

 

This is why they have made the journey after the famine of winter. Food is everywhere. Birds have flown in from as far away as the Arctic and subtropics. Canada geese join in flocks of white pelicans² to breed here. 

 

A snow-covered wasteland is transformed to an American Serengeti. But it's a landscape like no other. Geysers made Yellowstone famous. Yellowstone sets above the molten core of a volcano. Underground water become super-heated and erupts into the air. Strangely, geysers and hot springs can creep around the landscape. The curious shapes of grotto³ geyser are actually trees entombed and petrified⁴ by minerals dissolved in the water.

1 herds   

兽群( herd的名词复数 )； 牧群； 人群； 群众

参考例句：

• Regularly at daybreak they drive their herds to the pasture. 每天天一亮他们就把牲畜赶到草场上去。
• There we saw herds of cows grazing on the pasture. 我们在那里看到一群群的牛在草地上吃草。

2 pelicans   

n.鹈鹕( pelican的名词复数 )

参考例句：

• Kurt watched the Pelicans fire their jets and scorch the grass. 库尔特看着鹈鹕运兵船点火，它们的喷焰把草烧焦。 来自互联网
• The Pelican Feeding Officers present an educational talk while feeding the pelicans. 那个正在喂鹈鹕的工作人员会边喂鹈鹕边给它上一节教育课。 来自互联网

3 grotto   

n.洞穴

参考例句：

• We reached a beautiful grotto,whose entrance was almost hiden by the vine.我们到达了一个美丽的洞穴，洞的进口几乎被藤蔓遮掩著。
• Water trickles through an underground grotto.水沿着地下岩洞流淌。

4 petrified   

adj.惊呆的；目瞪口呆的v.使吓呆，使惊呆；变僵硬；使石化(petrify的过去式和过去分词)

参考例句：

• I'm petrified of snakes. 我特别怕蛇。
• The poor child was petrified with fear. 这可怜的孩子被吓呆了。 来自《简明英汉词典》