根据题目要求完成下列任务。用中文作答。 以下是一位老师在进行词汇教学时的情景： Step1复习(revision) 互致问候后，教师将装有彩色小图片的信封分发给各小组。 T：Open the envelopes, please. You have something nice in them. What are they? S：A green ear, a red ball, a blue plane, a yellow cat… T：What do you like? S：I like… Step 2导入(1eading in) PPT播放歌曲，师生共同演唱。 T：Let’s sing the song “Who Is Wearing Yellow Today”. 音乐结束后，教师并没有停下来，而是改编歌词继续唱。 T：Who is wearing blue today? Blue today? Blue today? Who is wearing blue today? Blue today? Step 3呈现 (presentation) T：Who is wearing blue today? S：You are wearing blue today. T：Yes, I’m wearing blue today. I’m wearing a blue sweater now. 学生跟读：sweater, sweater, blue sweater T：I like the blue sweater. If you like it, please say it out loud. PPT展示粉红色毛衣图片 T：Do you like the pink sweater? S：Yes, I like the pink sweater． （借助学生穿着的服装，引出jacket等新词，展开活动） T：It is too hot. I’ll take off my sweater. Please take off your jacket． （伴随动作，一次教授词组：take of, put on, hang up和put away） 根据以上所给的教学案例，回答下面问题。 教师在复习、导入及呈现环节创设了不同情境，请分别对其创设方法及作用进行分析。