问题补充：
-- ? --Yes, it is.
A. Is Bob a boy?
B. Are you ten?
C. Is your pen blue?
D. Is she here?
答案：
A. Is Bob a boy?
B. Are you ten?
(答案→)C. Is your pen blue?
D. Is she here?
解析：Is Bob a boy?鲍勃是个男孩吗？Are you ten?你十岁吗？Is your pen blue?你的钢笔是蓝色的吗？Is she here?她在这儿吗？根据下文，是的，它是。英语中it一般用来指前文提到的非生命的物品，故选C。
