SSS 2009-05-13_在线英语听力室_免费在线英语听力学习网站

(单词翻译:双击或拖选)

This is Scientific American's 60-second Science. I'm Karen Hopkin. This will just take a minute.

Hybrid¹ cars are good for the environment, but scientists say that they might be bad for pedestrians². Because hybrids³ are so quiet that can be hard for walkers to hear them until it’s too late. Listen to this,"...", that is a Toyota Prius moving at 5 miles an hour. If you didn’t hear anything, well, that’s what worries scientists at the University of California Riverside.

They recorded the sounds made by an approaching hybrid vehicle and by a car with a standard internal combustion⁴ engine. They then asked listeners wearing headphones to determine whether the car was coming from the left or the right. Turns out people could hear the standard vehicle from about 36 feet away, but the hybrid was able to sneak⁵ up to just 11 feet away before listeners knew where it was coming from. And when the scientists added some background noise, people couldn’t pinpoint⁶ the direction of the Prius until it had really passed them by, results they'll be presenting at the May meeting of the Acoustical⁷ Society of America in Portland, Oregon. The solution, they say, is to require a minimum sound for all late model cars, no annoying beeps or alarms, it's just something to supply that new car sound.

Thanks for the minute for Scientific American's 60-second Science. I'm Karen Hopkin.

点击

收听单词发音

1 hybrid
n.(动，植）杂种，混合物
参考例句：
That is a hybrid perpetual rose.那是一株杂交的四季开花的蔷薇。 The hybrid was tall,handsome,and intelligent.那混血儿高大、英俊、又聪明。

2 pedestrians
n.步行者( pedestrian的名词复数 )
参考例句：
Several pedestrians had come to grief on the icy pavement. 几个行人在结冰的人行道上滑倒了。来自《简明英汉词典》 Pedestrians keep to the sidewalk [footpath]! 行人走便道。来自《现代汉英综合大词典》

3 hybrids
n.杂交生成的生物体( hybrid的名词复数 )；杂交植物（或动物）；杂种；（不同事物的）混合物
参考例句：
All these brightly coloured hybrids are so lovely in the garden. 花园里所有这些色彩鲜艳的杂交花真美丽。来自辞典例句 The notion that interspecific hybrids are rare is ill-founded. 有一种看法认为种间杂种是罕见的，这种看法是无根据的。来自辞典例句

4 combustion
n.燃烧；氧化；骚动
参考例句：
We might be tempted to think of combustion.我们也许会联想到氧化。 The smoke formed by their combustion is negligible.由它燃烧所生成的烟是可忽略的。

5 sneak
vt.潜行(隐藏,填石缝)；偷偷摸摸做；n.潜行；adj.暗中进行
参考例句：
He raised his spear and sneak forward.他提起长矛悄悄地前进。 I saw him sneak away from us.我看见他悄悄地从我们身边走开。

6 pinpoint
vt.准确地确定；用针标出…的精确位置
参考例句：
It is difficult to pinpoint when water problems of the modern age began.很难准确地指出，现代用水的问题是什么时候出现的。 I could pinpoint his precise location on a map.我能在地图上指明他的准确位置。

7 acoustical
adj. 听觉的，声学的，音响学的
参考例句：
This system can set up acoustical resonances. 这种系统能产生共鸣。 The relevance of acoustical principles is by no means limited to sound and hearing. 声学原理并不仅仅适用于声音和听觉。