总的来说，Sitemaps 0.90协议对爬行效率提供了改进，而常规站点地图引用和组合的机器指令无法完成这点。

Overall Sitemaps 0.90 protocol offers an improvement in terms of crawling efficiency that cannot be accomplished using regular sitemap references and robot directives combined.

youdao

在例2中，一个业务策略指令是一个表达式，它是以下方面的组合。

In example 2, a business policy directive is an expression that is a mixture between.

youdao

可以通过 and 指令进行组合比较（注意可以用一个 xor 将所有逻辑指令结合成一个，但那样做的代码应该比这个要清晰很多）。

You then combine the comparisons using the and instruction (note that you could have combined all the logical instructions into one with an xor, but the code would have been much less clear).

youdao