偶然看到的英文：
light on ;light upon

参考例句：

I came across this quotation from Shakespeare in my reading last night
昨晚我在阅读中，偶然看到莎士比亚著作中的这段引语。

light是什么意思：
n. 光；光源；灯；点火物；日光；角度，眼光
v. 点，点燃；点着；照亮；用灯光指引
adv. 轻的，轻装的
adj. 浅色的；轻的；少量的；轻微的；（负担）轻的；轻盈的，轻快的；清淡的

The torch was lighted.
火炬点亮了。

I'm lost as a light is lost in light.
我如同灯盏迷失在光明里。

The saturation and lightness of light also affect our perceptions.
饱和度和亮度也影响到我们的感觉。

Ambient light: As the name suggests, this light is present everywhere.
环境光：就如其名所暗示，各处都存在光照。

The chamber was ablaze with light.
会议厅里灯火辉煌。

upon是什么意思：
prep. 在...上；紧接着；逼近；根据；走上...；爬上...

He stepped upon the alter.
他走上圣坛。

To bear hard upon;press.
使痛苦不堪对某人施加困难；逼迫

press hard upon
进逼|压迫|穷追

call upon; call on
应用;访问;号召;呼吁

Lay stress on / upon
着重,重视