Most teachers have never given online teaching classes, so this is a novelty for them, too. They have to learn to speak naturally in front of a camera, use digital red pens during presentations, and keep the students engaged online via written comments — not an easy feat with young kids or teenagers. 大多数教师从未上过网课，这对他们来说也是一件新鲜事物。他们必须学会在镜头前自然地说话，在演讲中使用红色数码笔，并通过打字评论让学生们保持在线参与感——一直集中精神对小孩子或青少年来说并不是一件容易的事。