2．教学B．Let-s wrap it up (1)教师讲解答题要求。 (2)学生独立填空。 (3)全班讲评订正。 3．教学C．Story time
(1)教师指着插图，先做背景介绍：
T:Look. Zoom and Zip are talking about changes. What are they talking about?Let's read。 (2)学生阅读故事，了解故事大意，画出不理解的句子。
(3)教师播放录像，学生边看录像边理解故事内容。在理解故事内容的基础上，让学生模仿故事中人物的语音、语调朗读下列句子：
Cavemen often ate raw meat. In 2050, there will be house robots. They didn't do the dishes either!
We should help the earth now, so birds will have homes and the forests will be healthy and green again.
Before humans lived on the earth, whales already lived in the sea. If we change now, whales and humans will have a bright future. Heal the world! Make it a better place!
四、巩固与拓展（Consolidation and extension）
活动：环保小达人
活动方式：学生六人一组，制作一份英文版的保护环境的宣传海报。可以介绍动植物界及人类的生存危机，也可以介绍一些环保小举措，一起争当“环保小达人”。海报制作完成后先在班级展示，评出奖项，如：“最佳创意奖”“最佳版面奖”，最后选出一些作品进行全校展示。 五、家庭作业（Homework） 1．听录音，进一步理解故事内容。 2．完成活动手册配套练习。
板书设计
Unit 4 Then and now
Cavemen often ate raw meat. In 2050, there will be house robots. They didn't do the dishes either!
We should help the earth now. so birds will have homes and the forests will be healthy and green again.
Before humans lived on the earth, whales already lived in the sea. If we change now, whales and humans will have a bright future. Heal the world! Make it a better place!