— When did you start to collect stamps?— I got my stamp when I was years old. A. one s

问题补充：

— When did you start to collect stamps?

— I got my stamp when I was years old.

A. one, seven

B. one, seventh

C. first, seventh

D. first, seven

答案：

A. one, seven

B. one, seventh

C. first, seventh

(答案→)D. first, seven

解析：句意:-你什么时候开始收集邮票的？-我在7岁的时候得到了我的第一张邮票。由句意可知，7岁的时候，应该是when I was 7 years old，应用基数词。而第一空是说得到了第一张邮票，故应用序数词。故选D。