优秀英语作文 | 小学英语作文 | 初中英语作文 | 高中英语作文 | 大学英语作文 | 中考英语作文 | 高考英语作文 | 考研英语作文 | 四级英语作文 | 六级英语作文
雅思英语作文 | 托福英语作文 | 奥运英语作文 | 应用英语作文 | 英语作文范文 | 英语写作技巧 | 英语小作文

展望(Vision)

2013-08-20 01:00
导读:四级英语作文范文,展望(Vision)应该怎么写,有什么格式要求,科教作文网提供的这篇文章是一个很好的范例:  human vision like that of other primates has evolved in an arboreal environment. in the dens

  human vision like that of other primates has evolved in an arboreal environment. in the dense complex world of a tropical forest, it is more important to see well that to develop an acute sense of smell. in the course of evolution members of the primate line have acquired large eyes while the snout has shrunk to give the eye an unimpeded view. of mammals only humans and some primates enjoy color vision. the red flag is black to the bull. horses live in a monochrome world .light visible to human eyes however occupies only a very narrow band in the whole electromagnetic spectrum. ultraviolet rays are invisible to humans though ants and honeybees are sensitive to them.

  humans though ants and honeybees are sensitive to them. humans have no direct perception of infrared rays unlike the rattlesnake which has receptors tuned into wavelengths longer than 0.7 micron. the world would look eerily different if human eyes were sensitive to infrared radiation. then instead of the darkness of night, we would be able to move easily in a strange shadowless world where objects glowed with varying degrees of intensity. but human eyes excel in other ways. they are in fact remarkably discerning in color gradation. the color sensitivity of normal human vision is rarely surpassed even by sophisticated technical devices.

    上一篇:2007年6月四级作文范文 下一篇:没有了