题目内容：
根据提供的信息和语言素材设计教学方案，用英文作答。设计任务：请阅读下面学生信息和语言素材，设计一节英语语法课的教学方案。教案没有固定格式。但须包含下列要点：
· teaching objectives
· teaching contents
· key and difficult points
· major .steps and time allocation
· activities and justifications
教学时间：45分钟
学生概况：某城镇普通中学九年级(初中三年级)学生，班级人数40人，多数已经达到《义务教育英语课程标准(2011版)》四级水平，学生课堂参与积极性一般。
语言素材：
Girl 1 : Where are you going, Larry?
Boy 1 : To Tom' s party.
Girl 1 : Lucky you !I' d love to go to that party !
Boy l : Yeah, well, I'm a little nervous. I don't know what to wear.
Girl 1 : If I were you, I'd wear a shirt and tie.
Boy 1 : What if everybody else is wearing jeans and T-shirts?
Girl 1 : Oh, you shouldn't worry about what other people are wearing.
Boy 1 : And I don't have a present. What if everyone brings a present?
Girl 1 : If I were you, I'd take a small present--a pen or something. Keep it in your pocket
and if everyone has a present, you can give him yours. If not, you can keep it.
Boy 1 : OK. But what if I don't know anyone?
Girl 1 : If you don' t know anyone, you can talk to Tom. He'll introduce you to people.
Boy 1 : I guess I can do that.
Girl 1 : Look !You' re sure to have fun. But if you' re still nervous, you can leave.
答案解析：