Click on "el patito Fito" (the little duck). The name of a color will appear and you must find the cat with that color and click on it.
If you are correct you will hear the pronunciation and the other images will disappear. You will get a small yellow smiley.
If you are incorrect, the image that you clicked on will disappear and you will get a green little face. Click on another image.
If you don't have Internet Explorer, it is possible that you can't hear the sound.