When you are introducing a new activity, make the first content- the first iteration simple and accessible to your students. They are already learning a new thing, that is, the new activity. Don't compound it by adding difficult content on top of it. Remember the minimal pairs in pronunciation teaching? They are minimal to prevent the learner from getting distracted by the other extraneous sound patterns. It's Beat vs. Bit. not treat vs. trick.
You can check it out here: http://www.youtube.com/watch?v=JXSeOWpac_c
Roger
You can check it out here: http://www.youtube.com/watch?v=RuWXZl7GZkY
Roger
Roger