5.29雅思口语跟读训练

Angela_passions

希望大家在跟读的时候可以多琢磨琢磨发音，音标还没完全巩固的小伙伴抓紧咯，音标在学英语的过程中是必不可少的。


今天我们听一段听力文摘关于麋鹿的文章。




Reindeer Eyes

Rudolph the reindeer is best known for his brightly colored rednose. For other reindeer, however, the most colorful thing about them is actually their eyes.Researchers have found that depending on the season, the eyes of Arctic reindeer change fromgold to blue.

Tapetum Lucidum
Like many mammals, Arctic reindeer have a structure in the eye called the tapetum lucidum, TL forshort. It sits behind the retina and reflects light back to increase the sensitivity of night vision. TheTL is also responsible for reindeer eye color changes.

During the Arctic summer, when it’s always light outside, reindeer TL is gold — a color that reflectsmore light back through the retina, better enabling reindeer to see in daylight. (This is why, by theway, many mammals have gold colored eyes.)


When Darkness Reigns
But when the Arctic winter sets in and darkness reigns, the TL turns blue. The result of this is lesslight reflecting back out through the retina, making it easier for the animals to see predators in dimconditions.

The color change may be caused by shifting pressure in reindeer eyes, which stems from constantpupil dilation. When compressed, the TL reflects shorter wavelengths of blue light which are moreplentiful during Arctic winters.