不是。。。就是

[Fred0]

I have encountered the construction 不是。。。就是 several times, and I don't understand it's meaning. Here a man (狗子) is walking barefoot on a hot dirt road and is looking for a grassy strip beside the road on which he can walk more comfortably, but he can only see rocks and sand.

 

狗子冲两旁瞭望, 想找草地走, 草地不烫脚 。可两旁没草地, 不是石头就是石头，不是沙子就是沙子。

 

It seems to be saying, "not rocks, then rocks; not sand, then sand." If the sentence is trying to say there was only rocks and sand, why isn't it 只是石头，只是沙, or 就石头，就沙？

[Publius]

不是……就是…… = either ... or ...

Usually it's 不是A就是B, but the author feels it's too mundane. Effectively he's saying 除了石头还是石头，除了沙子还是沙子. Well, that's the same meaning as 只有石头和沙子. But the mood is different. See this Zhihu entry about Lu Xun's famous sentence 在我的后园，可以看见墙外有两株树，一株是枣树，还有一株也是枣树。

[Fred0]

非常感谢！

[Beelzebro]

I'm very late to the thread, but for the benefit of future readers, I'll add what I think is a good English translation of this:

 

Quote

可两旁没草地, 不是石头就是石头，不是沙子就是沙子。  

But at neither side was there any grass, only rocks and more rocks, sand and more sand.