Analysis of Double-Listing

When searching in Google, you may notice an interesting phenomenon: some websites can be listed twice in a row:
For the above example, after we change the default 10 search results displayed on each page of Google to only 4 items displayed on each page, we can see that the two websites from the same address are now ranked first, and the other is ranked first (fourth) on the second page ).

We all know that for any keyword query, no matter how many webpages on a website are closely related to the query, Google only allows a list of up to two pages in the search results. So, when the rankings of these two webpages are relatively close or appear on the same search result page, what will Google do with data?
To verify our observations, we selected the following two webpages from the same website and ranked 3 and 17 respectively. When Google displays 10 search results on each page by default, they are on the first and second pages of the search results, but after we change the options to display 20 search results on each page, these two webpages appear on the first and fourth digits of the search results (as shown in the following figure ):
It is not difficult to know that this situation is not often caused by the fact that although Google may list two webpages on a website, it is often a far cry, for example, when one is on the 9th-bit, the other one is on the 156 bits, so it cannot appear on the same search result page.

However, if the two webpage lists under the same domain name appear on the same Google search result page at the same time, for example, one is 2nd and the other is 10th, google will integrate the two lists from the same site to display them to users. The result is displayed to the user with 2nd and 3rd names.
Note: this is just a phenomenon we have observed. No one knows why Google allows the same website to appear twice in the search results, no one can guarantee how long this practice will last.
Google provides off-the-shelf options in its "advanced search" item, showing 10, 20, 30, 50, and 100 search results per page, if you want to set a random value, you only need to search for "search? Add "num = xx &" (no quotation marks. For example, ""> http://www.google.com/search? Num = 9 & hl = en & lr = & ie = UTF-8 & c2coff = 1 & q = SEO ";
We know that it is Google's consistent policy to return the most important and most relevant search results to the user's query conditions. Following this policy, we provide you with some methods to increase the number of websites to be Double-Lisiting: