What challenges do teachers face with smart blackboards?

Remember the screech of chalk on a blackboard? In China, that sound has been replaced by the silent glow of electronic screens. This multi-billion dollar classroom upgrade promises a high-tech future for learning. But for parents, it brings a familiar worry. They fear we are sacrificing our children's eyesight for digital progress. So, is this a leap forward for education, or a step back for our kids' health? / Heart to Heart - please send your audio questions to roundtablepodcast@qq.com (16:18). On the show: Steve, Yushan & Yushun