Ding Yi's precious jade stone has disappeared! This jade stone is a 600-year-old object. Today, however, when Ding Yi wanted to take out the precious jade stone to show it to his friends, he found that it was missing.What is strange is that the doors and windows of his house were shut – how could it have gone?

“Smart Cat " has the following six features:

Feature one: original stories, readable.

Feature two: audio stories, diverse versions.

Feature three: outline closely, high coverage.

Feature four:  scientific choreography, high repetition rate.

Feature five: rich resources both online and offline.

Feature six: reading guidance, high practicability.