提示：点击单元就可进入课文学习：
- 课文目录与封面 课文录音与翻译
- Unit 1:Spring is coming!
- Unit 2:Plant a plant!
- Unit 3:Animals are our friends
- Unit 4:The internet connects us
- Unit 5:Buying and selling
- Unit 6:Be a champion!
- Unit 7:Know our world
- Unit 8:Save our world
- Pronunciation
- Vocabulary and Structures Grammar