人教版八年级下册英语教材共有十个单元，各单元名称如下：

Unit 1 What’s the matter？

Unit 2 I’ll help clean up the city parks.

Unit 3 Could you please clean your room？

Unit 4 Why don’t you talk to your parents？

Unit 5 What were you doing when the rainstorm came？

Unit 6 An old man tried to move the mountains.

Unit 7 What’s the highest mountain in the world？

Unit 8 Have you read Treasure Island yet？

Unit 9 Have you ever been to a museum？

Unit 10 I’ve had this bike for three years.

建议学生按照单元顺序逐步学习，每个单元都涵盖了不同的主题和语法知识，有助于全面提升英语水平。