Unit 13Were trying to Were trying to save the earth.save the earth.Section A 3a-4c学习目标Keywords&phrases:method，cruel，harmful，industry，law，afford，take part in，turn off，pay forKeysentences:1.Were trying to save the earth.2.The river used to be so clean.3.The air is badly polluted.新课导入新课导入There are some animals are endangered.We should do something to protect the animals and the environment!The zoos provide homes for many endangered animals.1.Have you ever seen a shark（鲨鱼）（鲨鱼）?2.What do you know abo
