教学背景：Language focus:To consolidate the sentence pattern “Trees can be used to do sth”To consolidate the sentence pattern “if there is no trees.”To learn the sentence “We can protect trees by doing.”Ability Target:To improve the students ability of speaking and listeningTo help the students know the importance of trees and how to protect them.Emotion Target: To encourage the students to protect trees in their daily life. To encourage the students to take care of the earth and protect the environment.ProcedureContentsActivitiesPurposeI.Pre-task Preparation1. Enjoy a song 2. read a poem. To make sentences according to the questions. To arouse the students interests. To show the importance of treesII.While-task procedure1) To show the posters and ask the students to complete the sentence Nature and environment2)Guess Whats our pollution fighters?3)Read the topic.4)Answer questions about trees5)Look and say：What can you see in the streets? 6) Group work. trees around us.7 sentences and put a tick or a cross in the correct boxes.To talk about the importance of the trees.To read the sentences.To do the pair work. Look at the pictures and say how trees protect our environment.)Make a dialogue. s. What can you see our school?Who is our good pollution fighters? To learn how to save water and ask the students to think about more ways.To use the sentence “We can save water by doing.” to express their opinionIII.Post- task activitiesA posterTo make a poster in groups.1)Enjoy a story and answer my questions.2)Retell the reading教学反思：环境污染是当今较为严重的问题，如何预防抵制污染是我们本单元要讨论的重要话题。因此，在本主题单元中,我设计了三个专题来组织活动.专题一,树在自然环境中的重要性,专题二,树的现状.专题三,我们应该怎样保护树,保护环境.重点通过学生的自主学习了解树对人类的作用,对大自然的作用,了解树的重要性.在日常生活中应如何爱护树木,节约生活用品,保护大自然.在教材学习的基础上,进行拓展和探究性的延伸.