Let's go straight to an example to understand what I'm talking about. What is the best way to write from the two options below?
<!-- Вариант 1 --> <meta name="keywords" content="купить автомобиль москва, купить автомобиль в москве"> <!-- Вариант 2 --> <meta name="keywords" content="автомобиль, купить, москва">
The second option is not very good because the site will be included in the search engine for those who simply type in "Moscow" or simply "Car", although of course it is far from the first place in the search results. But it is possible that the search engine automatically combines these words, turning the second option into the first (I don't know if this is so, that's why I'm asking).
If you look at the popular auto sales sites (rst, avito, infocar etc), they seem to also do not know the answer to this question. And they combine both queries. That is, your keywords will look like this from their point of view
<meta name="keywords" content="купить автомобиль мocква, купить автомобиль в мocквe, автомобиль, купить, мocквa">
But, as far as I know, although search engines look into these words, they are still actively looking into the content of the page. And here it is most important. Because if the keywords say the sale of a car, but in fact, likes are bought (and not even dogs), then the search engines can lower them in the search results.