根据题目要求完成下列任务，用中文作答。 以下是某堂课的教学材料：? Betty: Hi Mum, can you hear me? Mum: Yes, I can. Where are you? Betty: I'm standing on the Great Wall of China and talking to you. Mum: Really? Betty: We're on a school trip and we've having lunch. And we're lying in the sun and we'retaking lots of photos. Mum: That's great, Betty. What are the others doing? Betty: Well, Tony is eating an ice cream, and Lucy is buying some presents and postcards.And Tom is eating lunch and lying in the sun. Mum: Can you send me a post card? Betty: Yes. Lucy and I are writing postcards. We're enjoying the school trip a lot. Anyway,we're going home now. Bye! Mum: Bye bye, Betty! 根据材料内容回答以下三个问题。 (1)这份材料属于哪种语篇类型?(7分) (2)这份材料适合于哪种课堂教学?说明理由(至少写出两个要点)。(8分) (3)分析教师选用文本材料时需要考虑的基本要素(至少写出三个要点)。(15分)