I began the session with Piero by having him use the correct form of ON, AT, TO, and ON in the context of numerous sentences. I then had him insert HOW MANY, HOW MUCH, WHOSE, WHAT, WHERE, WHEN, or WHY to numerous questions that showed the answer, so he would know the correct word that should begin the sentence. We then wrote conversational questions to each other. I discussed and explained all errors and misunderstandings Piero experienced.