英语听力：自然百科 澳大利亚大堡礁 Great Barrier Reef—17

 "One of the early methods to getting rid of a starfish was to cut them in half, then killing¹ them with a knife, but starfish has this amazing property when they regenerate²."

 

Far from killing them, cutting these animals in half actually creates two of them. They have to be physically³ picked off the reef or injected with poison to control their numbers. Today pollution levels have dropped and so has the Crown-of-throne's population, for now anyhow.

 

But there are worse things of the modern world that's doing to the reef. Even the smallest changing climate upsets the natural order here. The turtles are already feeling it. Their eggs are very heat-sensitive. With higher temperatures, fewer eggs are hatching. And the turtle population is in decline. In 40 years, there may be none left.

 

And the coral reef itself is in grave danger, because water temperature is a matter of life and death. A change of just one or two degrees can wipe it out.

 

The scientists are discovering that coral isn’t totally defenseless. It has a protection mechanism⁴ that defies belief. If temperatures get too hot, coral responds by trying to change the weather. It exudes⁵ an invisible chemical, the floats above the water, and encourages clouds to form, providing shade on the hottest days.

1 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

2 regenerate   

vt.使恢复，使新生；vi.恢复，再生；adj.恢复的

参考例句：

• Their aim is to regenerate British industry.他们的目的是复兴英国的工业。
• Although it is not easy,you have the power to regenerate your life.尽管这不容易，但你有使生活重获新生的能力。

3 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

4 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

5 exudes   

v.缓慢流出，渗出，分泌出( exude的第三人称单数 )；流露出对（某物）的神态或感情

参考例句：

• The plant exudes a sticky fluid. 这种植物分泌出一种黏液。
• She exudes sexual magnetism. 她洋溢着女性的魅力。