问题补充：
The stamps were according to their styles and features.
A. found out
B. sorted out
C. put out
D. taken out
答案：
A. found out
(答案→)B. sorted out
C. put out
D. taken out
解析：本题考查动词短语辨析。find out“发现，找出”；sort out“分类”；put out“扑灭(火)”；take out“提取出”。句意为：这些邮票根据它们的样式和特点被分类出来。
