HKPPDA is an integrated Mandarin learning and assessment application specially customized for children in Hong Kong. It is deeply in line with the language learning characteristics and actual needs of Hong Kong children. It uses innovative technology and rich resources to explore the achievements and potential of children's Mandarin learning in an all-round and multi-level way. We are committed to providing children with an accurate, scientific, interesting and efficient Mandarin learning experience, effectively improving the fun and practicality of the language learning process, fully meeting the learning and teaching needs of Hong Kong children in Mandarin, and helping them move forward steadily on the road to learning Mandarin.