A:1+32,1-32
B:1-32,1+32
C:1+32,1-32-1+32,-1-32
D:1-32,1+32-1-32,-1+32
-- It seems that you know a lot about the story.
-- Well. I ____ (read) it many times.
表层土的养分来自腐烂的动植物的遗体,它们被称为____。