There are places to look online to find a song with only a few lyrics. Once you place the words you do know into the search engine, all sings with those lyrics will pop up. You will need to search through the songs to see which one is your song. For a place to search for a song with only a few lyrics go to, http://findmeatune.com/.
Many lyrics websites only require a line or two of a song to match it against their database. Quite often, fans who only have a few lyrics, or just a part of the chorus, can easily find what they're looking for. lyricsfly.com/