案例：在基本不等式：（a+b）/2≥
，b∈R+（R+表示全体正实数的集合），当且仅当a=b时等号成立的教学中，两位教师创设了如下情境：
情境1：某商店在“双十一”进行商品降价促销活动，拟分两次降价，有三种降价方案：甲方案是第一次打P折销售，第二次打Q折销售；乙方案是第一次打Q折销售，第二次打P折销售；丙方案是两次都打(Q+P)/2折销售，请问哪一次降价最多？
情境2：现有一台天平，两臂之长略有差异，其他均精确，有人要用它称量物体的质量，只需将物体放在左右两个托盘中各称一次，再将称量结果相加后除以2，就是物体的真实质量，你认为这种做法对不对？如果不对的话，你能否找到一种用这台天平称 量物体质量的正确做法吗？
问题：（1）请对上述的两种情境创设给予评价。（10分）
（2）数学教学中情境创设应该注意哪些问题？（10分）
参考答案
参考解析
【分析题】
【分析题】
设计任务：阅读下面的学生信息和语言素材，设计20分钟的阅读教学方案。
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：20分钟
学生概况：某城镇普通中学八年级（初中二年级）学生，班级人数40人。多数
学生已经达到《义务教育英语课程标准（2011年版）》三级水平。学生课堂参与积极性一般。
语言素材：
David's Hobbies
Many students have hobbies，such as reading，painting，growing vegetables and looking after animals.Some hobbies are relaxing and others are active.Hobbies can make you grow as a person，develop your interests and help you learn new skills.
David Smith is a student，and one of his hobbies is writing.During the summer of 2010，he spent four weeks at a summer camp.As well as the usual activities，such as sailing and climbing，there was a writing class.The teacher was a writer，and she asked them to talk about their lives and tell interesting stories.Then she encouraged them to write about their experiences at the camp.
Back at school，David wrote a story about the life of a sixteen-year-old boy，and it cameout as a book in 2012.Many young people love his book，and as a result，David has become a successful young writer
David has been very lucky because his hobby has brought him pleasure and success.But writing is not his only hobby. He is also interested in many other things. "I like playing volleyball too,"says David. "I spend some of my free time playing volleyball for my school team. Maybe I' ll write about my volleyball team in my future books."
【分析题】
案例：
某校初二(2)班，学生38人。
教学内容：耐久跑的终点冲刺。
教学要求：提高反应速度，掌握耐久跑的终点冲刺方法。
教学重点：耐久跑终点冲刺技术。
教学步骤：
(1)上课。教师提问耐久跑的终点冲刺的要点，即如何在耐久跑中节省力气？如何在冲刺时调动保存的体力？
(2)教师在学生回答的基础上总结，讲解规范姿势的要点：一是跑步过程中时刻调整呼吸；二是冲刺前就要调整肌肉状态，使腿部肌肉克服乳酸转化的酸胀感。
(3)准备运动：①四面转法；②齐步走、跑步走；③各关节活动。
(4)终点冲刺跑练习。
①介绍冲刺跑的动作要领、练习方法以及目标要求；
②分组成纵队站立于起跑线上，听哨音做后蹬跑20米过终点线，练习2—3次；
③小组间进行竞赛练习跑，分组听哨音用站立式起跑做不同距离的终点冲刺跑，练习80米×3次、100米x2次、150米X1次。关于具体练习运动量，学生可根据自己的体力选择适当的冲刺距离。
(5)课堂小结。对教学效果进行评价，对学生的表现进行点评，对优秀学生表示肯定，并布置课后练习作业。
问题：
(1)这节课的教学组织形式是什么?(7分)
(2)分祈该案例中教学的优缺点。（8分）
