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https://learn.plus/2016/07/06/%e7%bf%bb%e8%bd%89%e6%95%99%e5%ae%a4%e5%a5%bd%e5%b7%a5%e5%85%b7%e4%bb%8b%e7%b4%b9%ef%bc%9aversal/
翻轉教室好工具介紹:Versal