Passive voice in the past continuous and past perfect tenses
u 内容分析：
本板块围绕单元话题,首先通过一篇关于城市半程马拉松的博客文章，引导学生观察、探究过去进行时和过去完成时的被动语态在文中的使用情况，归纳过去进行时和过去完成时的被动语态的核心规则；然后通过句子、语篇两个层面的练习巩固所学；最后再让学生正确使用目标语法完成相关活动，学以致用。
u 教学目标：
By the end of this section, students will be able to:
1. identify the use of the passive voice in the past continuous and past perfect tenses;
2. work out the rules of the passive voice in the past continuous and past perfect tenses;
3. use the right tenses to finish related tasks;
4. apply the passive voice in the past continuous and past perfect tenses in new contexts.
