An image of my mother's light-the-world smile--the one before it all happened--flashed in front of my eyes.

我母亲在生病以前、简直能照亮全世界的灿烂微笑的画面又映现在我眼前。

One of them even turned back to look at him, and although he could not see him clearly, the man's eyes shone with a lustful light, like a famished person's at the sight of food.

一个还回头看他，样子不甚分明，但很像久饿的人见了食物一般，眼里闪出一种攫取的光。

However, using light to find one's own way around requires vastly more energy, since the eyes have to detect the tiny fraction of the light that bounces off each part of the scene.

但是，眼睛必须去识别周围景象反射的细微光线，所以若要用光线来探路就需要远远比这多的能量了。