V-ERG
(使)(血管)扩张;(使)(瞳孔)放大
When things such as blood vessels or the pupils of your eyes dilate or when something dilates them, they become wider or bigger.
例句
At night, the pupils dilate to allow in more light...
到了晚上，瞳孔就会扩大以接收更多光线。
Exercise dilates blood vessels on the surface of the brain.
运动会使大脑表层的血管扩张。