Carotene(the yellow substance in carrots) is a precursor of Vitamin A, which accounts for the saying that eating carrots helps you to see in the dark.

• 胡萝卜素（胡萝卜中的黄色物质）是合成维生素A的前体物质，所以说多吃胡萝卜帮助维持黑暗中的视力。