•Google the two possible forms and check which one is more common. For example, if you Google "the same than" and then "the same as", the latter has one thousand times as many results and so is obviously correct. If the result isn't so clear or you think it could be a common mistake even for native speakers, try the same thing with a Google Books search. It is important to always use quotations marks ("") around the search terms to make sure the words are together on the page.