Lesson 18 Cats and Dogs 第18课 猫和狗 1. What is it? 1. 它是什么? cat 猫 dog 狗 goat 山羊 sheep 绵羊 2. Let's sing a song. 2. 来唱一首歌。 Old MacDonald had a farm, E-I-E-I-O. And on his farm he had a cow, E-I-E-I-O. With a moo...