public String fullSource(){
  if (fullSource == null) {
    fullSource=addSentenceMarkers(source());
  }
  return fullSource;
}

public String fullSource ( ) { if ( fullSource == null ) { fullSource = addSentenceMarkers ( source ( ) ) ; } return fullSource ; }
returns a sentence with the start and stop symbols added to the beginning and the end of the sentence respectively
