【正文】 g to save them． Boy : Why? Are they endangered? Man : Yes． There used to be a lot of manatees, but now there aren’t very many of them． Boy : Do you know how many there are? Man : At this point, there are only about 2 500 in the U． S． In 1972, it was discovered that they were endangered． Since then, the government has passed laws to protect them． Boy : Where do they live? Man : Their favorite habitat is the water under the trees in mangrove swamps． Boy : And why are they endangered? Man : Some of the swamps have bee polluted． Also, there sometimes isn’t enough food for all of them． As you can see, they’re large． The average manatee is about three meters long and weighs about 1 000 pounds． They need about 100 pounds of aquatic feed a day． Boy: Aquatic feed? Man: Oh, that’s underwater plants and vegetation． That’s what they eat． Step Ⅲ 2b This activity provides listening practice using the target language． Go through the instructions with the class． Look at the headings in the chart and the blanks next to each heading． You will hear the same recording again． This time listen carefully to what both people say and fill in the blanks in the chart． Look at the sample answer． The two people on the recording are talking about manatees, so you write the word manatee after the words kind of animal in the chart． Play the recording again． Get students to fill in the blanks in the chart． Check the answers with the class． Answers Kind of animal: manatee Numbers: 2 500 in the U． S． Habitat: water under trees in mangrove swamps Reason why they are endangered: swamps polluted, not enough food Description : large, three metres long, weighs 1 000 pounds Step IV 2c This activity provides guided oral practice using the target language． Look at the sample conversation in the box． Invite a pair of students to read it to the class． SA : How big are manatees? SB : They’re about l0 feet long and they weigh about 1 000 pounds． Read the instructions aloud to the class． Each pair of students can make a conversation using information from Activities 2a and 2b． Let students work in pairs． While they are working, move around the classroom, checking the progress of the pairs and offering help as needed． When students finish the work, ask one or two pairs to say their conversations to the class． Conversation 1 SA: Where do manatees live? SB: They live in the water under the trees in mangrove swamps． Conversation 2 SA : Why are manatees endangered? SB : Because some swamps have been polluted． And there isn’t enough food for all the manatees, either． Step Ⅴ Grammar Focus Look at the grammar focus box． Invite five students to read the statements to the class． We’re trying to save the manages． Manatees eat about 100 pounds of food a day． There used to be a lot of manatees． In 1972, it was discovered that they were endangered． Some of the swamps have bee polluted． Put the class in five groups and ask each group to bee experts in one of the verb tenses and presents a review of that tense to the rest of the class． Have the students explain what the verb tense is used for and then give some sample sentences． Students can look back at the units where their verb tense was presented or practiced． Present progressive: Reviewed throughout the book． Present: Reviewed throughout the book Past with used to: Unit 4 Passive voice: Unit 10 Present perfect: Unit 14 While the groups are working, walk around the classroom helping the students with their explanations and their sample sentences． Ask one student of each group to show their work． As the students show their work, ask questions and correct any errors in their explanations or sentences． （ 1） Present progressive: One form of the verbs that express action that continues over a period of time, also called Present continues tense． The structure is am/is/are+ ing． For example: He is reading a story book． （ 2） Present: It is used for indicating action that is usual and habitual． The form of the verb is do or does． For example: I go to school by bike． She does her homework every day． （ 3） Past with used to: The structure of used to + inf． indicates a constant orfrequent practice in the past． For example: I used to go swimming when I was a child． （ 4） Passive voice: The form of the verb is be + p． p in the sentence． For example: Our classroom is cleaned every day． （ 5） Present Perfect: The from of the verb is have/has + p． p For example: I have already finished my homework． Step Ⅵ Summary In this class, we’ve learned some important words, such as endangered, mangrove swamps, habitat, aquatic feed． We’ve also learned the target language How big are manatees? They’ve about 10 feet long and they weigh about 1 000 pounds． At last, we reviewed some grammar we have learned． Step Ⅶ Homework 1． Make conversations in pairs to review the target language． 2． Make five sentences to review the grammar focus． Step Ⅷ Blackboard Design Unit 15 We’re trying to save the manatees! Section A The Second Period Make sentences to review the grammar focus: （ 1） He is reading a story book． （ 2） I go to school by bike． She does her homework every day． （ 3） I used to go swimming when I was a child． （ 4） Our classroom is cleaned every day． （ 5） I have already finished my homework． Unit 15 We’re trying to save the manatees! The Third Period Ⅰ． Teaching Aims and Demands 1． Knowledge Objects （ 1） Key Vocabulary against, be suitable for, tiny cages, educate, care for, urge （ 2） Target Language I think that animals should not live in zoos． I disagree with you． I feel that zoos provide clean and safe places for endangered animals to live． 2． Ability Objects （ 1） Train students’ integrating skills．