unit 3 教材背景链接 课件 人教版选修7
unit 3   教材背景链接 课件 人教版选修7第5页

★Complete the two sentences according to the passage. 1.Killer whales belong to the type of __________. 2. __________include the Blue Whales. Keys:1. toothed whales 2. Baleen whales