The key now is to see if the webpage refreshes correctly or if it refreshes with errors on the page.
If you refresh the page with the single quote added to the end of the URL and it loads 100% the same as it did originally then it is not vulnerable to SQLi and you can move on to the next link from our Google results page.
If however it does not refresh 100%, it is an indication that the page is potentially vulnerable to SQLi.
Key indicators that the page is vulnerable may simply be missing items like text/pictures/banners/etc,
or it could be one of the following messages appearing on the refreshed page (possibly associated with some type of error report):