Physics teacher surprised in his last class

<p>Right before Cheng, a physics teacher, gave his last class before his retirement, he was surprised by his students. In their own way, Cheng&#39;s students pay tribute to him, expressing their gratitude with flowers. Cheng is impressed and moved by this pleasant surprise.</p><p><span style="color: rgb(127, 127, 127);">(Produced by Lin Ziwei and Dong Feng)</span></p>