The great poet Li Bai of the Tang Dynasty, in his childhood, read classics and historical books. These books were very profound, and he found them boring and difficult to understand at first. So he put down his books and ran away from school to play.

He wandered around, looking everywhere. He saw an old woman sitting on a low stool by a grindstone, holding a thick iron rod and grinding it repeatedly on the stone. She was so focused that Li Bai knelt down in front of her without her noticing.

Li Bai didn't know what the old woman was doing, so he asked curiously, 'Grandma, what are you doing?' 'Grinding a needle,' the old woman replied simply without raising her head, continuing to diligently grind the iron rod in her hand.

'Grinding a needle?' Li Bai was confused. What the old woman was grinding was clearly a thick iron rod, how could it be a needle? Li Bai couldn't help but ask again, 'Grandma, needles are very, very tiny, but you're grinding a thick iron rod!'

The old woman continued grinding and said, 'I am indeed going to grind this iron rod into a tiny needle.' 'What?' Li Bai was surprised and blurted out, 'Can such a thick iron rod really be ground into a needle?'

At this point, the old woman finally raised her head, looked kindly at young Li Bai, and said, 'Yes, this iron rod is thick and large, and it's very difficult to grind it into a needle. But I grind it every day without stopping, and one day, I will turn it into a needle. Child, as long as you put in deep effort, even an iron rod can be ground into a needle!'

Young Li Bai was a child with great insight. Upon hearing the old woman's words, he suddenly understood a great deal. He thought to himself, 'That's right! As long as one has perseverance and persists every day, anything can be accomplished. Studying is the same; even if there are parts I don't understand, as long as I persist in reading more, reading every day, I will eventually understand.'

Realizing this, Li Bai felt deeply ashamed, his face burning. So he rushed home, returned to his study, opened the books he previously couldn't understand, and continued reading.