be the first/second 与be first/second有什么区别

问题描述:

be the first/second 与be first/second有什么区别
例题:That is Kangkang's ___pen .
A the second B second
注:the second 有第二的意思而second表示第二次,为什么答案是B

有kangkang's 就不用the, 因为已经是定指.