该句使用一般现在时描述历史来源，结构清晰。
The idiom "Catching Fireflies and Reading by Snowlight" originates from the Jin Dynasty. "Catching Fireflies" refers to Che Yin, who came from a poor family and could not afford lamp oil but wanted to study at night, so he caught fireflies in the summer to use as light. "Reading by Snowlight" refers to Sun Kang, who used the reflection of snow to read during winter nights. Later, the idiom came to symbolize diligent studying despite poverty.
During the Jin Dynasty, Che Yin was studious from a young age, but his family was poor, and his father could not provide proper learning conditions. To sustain basic needs, there was no extra money to buy lamp oil, so he had to use limited time to recite poetry and texts. One summer night, while reciting in the courtyard, he noticed many fireflies flying at low heights, their flashing lights standing out in the darkness. He thought, if he gathered many fireflies together, wouldn't they form a lamp? So he took a white silk bag, caught several dozen fireflies and put them inside, then tied the bag and hung it up. Although the light was dim, it was just enough to read by. From then on, whenever there were fireflies, he would catch some to use as a lamp. Thanks to his diligence, Che Yin later became a high-ranking official.
“囊萤映雪”这则成语的“囊萤”出自晋代车胤家境贫寒，无力购买灯油，却希望晚上读书，于是夏天晚上抓萤火虫当灯照明；“映雪”则是晋代孙康冬夜利用雪的反光阅读。后来，“囊萤映雪”用来比喻家境贫苦而刻苦读书。
晋代时，车胤自幼好学不倦，但家境贫困，父亲无法提供良好的学习条件。为了维持温饱，他没有多余的钱购买灯油，只能利用有限时间背诵诗文。一个夏夜，他在院子里背诵文章，忽然见许多萤火虫在低空飞舞，闪烁的光点在黑暗中格外显眼。他想到，如果将许多萤火虫集中起来，不就成了一盏灯吗？于是，他找来一只白绢口袋，抓了几十只萤火虫放入其中，再扎紧袋口挂起来。虽然光线不强，但勉强可用来看书。从此，只要有萤火虫，他便抓来当作照明。由于勤学苦练，车胤后来成为官位很高的人。