想想这个问题
How many points are there on the globe where by walking one mile south, one mile east and one mile north you reach the place where you started.
译:地球上有多少个点是向南走1公里,让后向东走一公里,然后向北走一公里还回到开始的这个点。
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讨论一下,看谁能想的比较全...