has not seen for a long time
好久不见了吗
以上为机器翻译结果，长、整句建议使用 人工翻译 。
youdao
It's not known when Mars was found and by whom Mars has been known for a very long time, and one of the planets that can be seen from the Earth without a telescope.
在很长一段时间里，没人知道火星是什么时候被发现的，谁发现的，也不知道有一种行星可以不用望远镜就能从地球上看到。
And so for a long time, but has not been seen!
因此，很长一段时间，但一直没有！
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