1. (2020·建邺模拟) 假如你是阳光中学的学生苏华，你的美国笔友 David 给你写了一封电子邮件，想了解你对网课学习的看法和建议。请根据邮件内容，用英语给他写一封回信。

Dear Su Hua,     Glad to hear that everything goes well in Nanjing, and you have been back to school for over two months. But now we have to stay home and study online because of the COVID-19.     What do you think are the advantages and disadvantages of online classes? Could you give us some useful suggestions to learn better online?     I'm looking forward to your reply. Yours, David