Great idea! I'm from China too, and loved the Hundred Thousand Whys book series when I was a child. However, there aren't much time to read those books anymore due to busy schedule. I like that it's clean, free, no ads, no signup required. Thanks for sharing it.

Fun fact: the original A Hundred Thousand Whys book only had ~3000 questions despite the name. We're already at ~2500 now, around 1500 of them are generated dynamically during user scroll. It can eventually hit a million — though we've learned that quantity without quality is worthless ;)