What Is the 'Three Character Classic'?

An Jiuyue squatted down and asked her sons softly, "Zheng'er, Rong'er, what did the teacher ask you?"

She was talking to another teacher and did not notice what this angry teacher said to her two sons.

She could not help but mutter, "These two aren't the type to offend others when they open their mouths to speak, though?"

Qian Yizheng glanced at the teacher standing at the school gate, still looking angry at them.

Then he looked at his mother and whispered, "The teacher asked us if we had read the 'Three Character Classic' at home.

"Brother told him he'd never heard of the 'Three Character Classic'. He even consulted the teacher about it, but then the teacher got angry."

"Mother, what is the 'Three-Character Classic'? Is it also a book?" Qian Yirong asked.

Is the 'Three-Character Classic' a very important book that we have to read? Is that why the teacher is angry at us?

An Jiuyue was extremely shocked.