Term1 Term2 Term3 - retrieve documents matching any of the search terms.
Documents matching multiple search terms score higher.
So, the search string is really asking for documents that contain the term X , but do not contain the term Files . The actress's name is Jenny McCarthy . But, if you check your spelling, you'll often get better results. Actually, it is asking for documents that contain Truck where the term Ford is optional. If all else fails, try adding more optional search terms or reducing the number of required terms.