I will switch every light bulb that's divisible by two.

我会按下编号能2的那些灯泡。

I know that because two is divisible into eight.

我知道这个 因8能2。

So in the 16th Century, Pope Gregory XIII tweak the system again so that leap ears would occur in any year that's divisible by four, but only in centuries that are evenly divided by 400, confusing, I know.

所以在16世纪，教皇格里三世再次修改了系统，使得闰年发生在每四年一次的年份中，但只有能400的年份才是闰年，令人困惑，我知道。