doraemon wa sensei ni natta koto ga aru

～ことがある (~koto ga aru)

:: pronounciation and sentence examples are available in the next post, Letter of The Grasshopper (Japanese song) : http://www.japaneseonline.org/2009/11/song-the-letter-of-grasshopper/::

Meaning : Someone has done something, someone has had an experience doing something; There [...]