【英语时差8,16】瞳孔（下）

 Like a theater curtain, a slit¹ pupil can close as much as necessary to prevent too much light from entering the eye. For humans and other animals active mainly in the daytime, visual sensitivity is not as important as the ability to see small details in bright light. So the eyes of humans, lizards², ground squirrels, and most birds have a design suited for operation in bright light without the special protection of slit pupils. In dim light, our eyes are not as sensitive as those of nocturnal animals. Of all pupil shapes found in vertebrates — animals with backbones³ — round pupils are the most common. Non-circular pupil shapes found in vertebrates include not only the vertical⁴ slits⁵ familiar to us from cats’ eyes, but also horizontal slits, crescents, heart shapes, and keyhole shapes.

1 slit   

n.狭长的切口；裂缝；vt.切开，撕裂

参考例句：

• The coat has been slit in two places.这件外衣有两处裂开了。
• He began to slit open each envelope.他开始裁开每个信封。

2 lizards   

n.蜥蜴( lizard的名词复数 )

参考例句：

• Nothing lives in Pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外，没有别的生物。 来自辞典例句
• Can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗？ 来自辞典例句

3 backbones   

n.骨干( backbone的名词复数 )；脊骨；骨气；脊骨状物

参考例句：

• Why do hummingbirds and gorillas both have backbones? 为什么蜂鸟和大猩猩都有脊骨？ 来自辞典例句
• Simply adding bandwidth to the Internet backbones is not an answer. 只是简单的在互联网骨架上增加带宽是应付不了的。 来自互联网

4 vertical   

adj.垂直的，顶点的，纵向的；n.垂直物，垂直的位置

参考例句：

• The northern side of the mountain is almost vertical.这座山的北坡几乎是垂直的。
• Vertical air motions are not measured by this system.垂直气流的运动不用这种系统来测量。

5 slits   

n.狭长的口子，裂缝( slit的名词复数 )v.切开，撕开( slit的第三人称单数 )；在…上开狭长口子

参考例句：

• He appears to have two slits for eyes. 他眯着两眼。
• "You go to--Halifax,'she said tensely, her green eyes slits of rage. "你给我滚----滚到远远的地方去！" 她恶狠狠地说，那双绿眼睛冒出了怒火。