下列教学片段选自某高中课堂实录，阅读后回答问题。 T: Today we are going to talk about "travelling". Mike, have you ever traveled M: Yes, I have ever been to Beijing. T: When did you go there M: Last summer. T: How did you go there M: We went there by bus. T: Why did you go there by bus M: Because it isn′t too far away from here and it′ s very convenient to go there by bus. T: Good. How about you Li Ming, have you ever travelled L: Yes, I have been to Hainan last winter vacation. T: How did you go there L: I went there by plane. T: Why L: Because it′s too far from here and we can save lots of time by going there by plane. Ask more students like this. 根据上面所给信息，回答下面三个问题： (1)该片段反映了教学中哪个环节 (2)分析该教学环节的目的。 (3)从教学有效性角度评析这个片段。