阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。

    Today is Friday. Linda says to her aunt on the telephone. "Aunt Mary, I'm sorry. I can't go ____ your farm tomorrow. Let us meet next Sunday."

    Aunt Mary says, "Oh, I'm sorry to hear that. I have ____ new dog. It is two years old. You can play with it on my farm."

    Linda says, "What's ____ (it) name?"

    Aunt Mary says, "Wangwang."

    Linda says, "Is it brown?"

    Aunt Mary says, "No, it is black. You know, it's my favourite colour.

    Linda says, "Yes, I think Wangwang ____ I can be good friends. See you next Sunday."

    Aunt Mary says, "____ (see) you."

①赤道是划分纬度的起点线，是90°纬线

②赤道是划分经度的起点线，是0°经线

③赤道是南半球和北半球的分界线

④赤道是南、北纬度的分界线

已知2³×8³=2ⁿ，则n的值是（        ）