Unit 15 Health Unit 16 Fire! Unit 17 Nature Unit 18 Jewels Unit 19 jobs Unit 20 Revisi N_Unit 21 Reading and Writing Unit 22 Britain and Ireland Unit 23 Rescuing the Temple Unit 24 The Science of Farming Unit 25 AT the Conference Unit 26 Revisi N_Additional Passage A Keeping Fit Additional Passage B A Good Servant Additional Passage C Baiji