下面是某英语教师在写作课的教学片段．阅读并回答问题。 Tell students we would write an article for our favorite sports, and the topic is about sports. Show students a model article on the screen and lead them to find out the format of anarticle: main heading, smaller heading and the body. Run a brainstorming activity: show some pictures about the sports and the famous athletes. Ask students the questions as follows. Why are you interested in that sport Who is your favorite athlete What do you do to improve your skills Then I would ask them to have a discussion about the above questions. They can change theirideas with their partners and find out the similarities and differences. Then choose one idea towrite with. After the discussion, I would pick some students to report their topics at the front. 根据上面的课堂教学片段回答下面三个问题： (1)该片段属于什么教学环节体现了哪种写作教学模式 (2)请从写作教学原则的角度，评价该教学片段。 (3)该片段中教师的课堂角色有哪些