题干
----Is this your pen? ---- .It's Tony's pen.
A：Yes, it is
B：No, it isn't
C：Yes, I am
D：No, I am not
答案(点此获取答案解析）
B
----Is this your pen? ---- .It's Tony's pen.
A：Yes, it is
B：No, it isn't
C：Yes, I am
D：No, I am not
的最大值与最小值情况是 （ 
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