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20分钟的英语阅读教学方案。教案没有固定格式，但须包含下列要点：
·teachingobjectives
·teachingcontents
·keyanddifficultpoints
·majorstepsandtimeallocation
·activitiesandjustifications
教学时间：20分钟
学生概况：某城镇普通中学七年级(初中一年级)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)》二级水平，学生课堂参与积极性较高。
Teaching Contents: A passage about online shopping.
Teaching Objectives:
(1) Knowledge objectives
①Students can master the main idea of this passage.
②Students can learn the advantages and disadvantages of online shopping.
(2) Ability objective
Students can improve their reading and communicating abilities through class activities.
(3) Emotional objective
Students can improve their confidence of learning English*, and be not afraid of speaking English in class.
Teaching Key Points:
①Students can understand the advantages and disadvantages of online shopping.
②Students can comprehend the main idea of the passage.
Teaching Difficult Point:
Students can have a reasonable consumption online.
Major Steps:
Step 1 Pre-reading (6 minutes)
(1) Show some questions on the blackboard and ask students to have a discussion.
①Do you know how to buy something on the Internet
②Do you often buy things on the Interact
③What can you buy
(2) Ask students to predict the main idea of this passage.
(Justification: This step can arouse students' interest, and let them know the topic of this reading class.)
Step 2 While-reading (8 minutes)
(1) Fast reading
Ask students to read this short passage quickly in oneminute, and then conclude the main idea of each paragraph.
Ask students to examine their forecasts and conclude the main topic of this passage.
(Justification: Students can develop their skimming ability in this step.)
(2) Careful reading
Let students read this passage carefully again.
Show the table on the blackboard and ask students to discuss about the online shopping. Then ask some studentsto share their answers.
(Justification: Different ways of exploiting the text can help students not merely to cope with one particular textin class but to develop their reading strategies and reading ability.)
Step 3 Post-reading (6 minutes)
Choose two volunteers to have an interview about online shopping. One student acts as interviewer and the otherinterviewee. The knowledge they have learned in this class needs to be used in this interview.
(Justification: Students have the interview in their own way, which helps to make practical use of what they learnin this period. At the same time, students can have a better understanding of the topic.)
