Unit 13 We’re trying to save the earth. Section A 第三课时 (3a -4c) shark n. 鲨鱼 fin n. (鱼)鳍 cruel adj. 残酷的;残忍的 harmful adj.有害的 3a Read the passage about sharks and complete the fact sheet below. Where shark fin soup is popular Number of sharks caught and traded every year How much the numbers of some kinds of sharks have fallen in the last 20 to 30 years Two environmental groups against “ finning” 3b so Read the passage again and fill in the blanks with the words in the box. although if but when 1. Many people do not realize they are killing a when whole shark ___________ they enjoy a bowl of shark fin soup. 2. Sharks are at the top of the food chain, _______their numbers drop, the ocean’s so ecosystem will be in danger. 3. Many think that sharks are too strong to but be endangered, ____________ they are wrong. Although there are no scientific studies 4. __________ to support this, a lot of people believe that shark fins are good for health. 5. Sharks may disappear one day __________ if we do not do something to stop the sale of shark fins. Grammar Focus We’re trying to save the earth. The river used to be so clean. The air is badly polluted. No scientific studies have shown that shark fins are good for health. We should help save the sharks. Present progressive Used to Passive voice Present perfect Modal verbs 4a Fill in the blanks with the correct forms of the verbs in brackets. Have taken Joe: __________ you ever __________ (take) part in an environ