unit one notice,poster and note unit two advertisin(Ⅰ) unit three advertisin(Ⅱ) unit four direction for use unit five invitation unit six letters of job application unit seven application for school attendant unit eight letters of recommendation unit nine resume unit ten inquiry and offer unit eleven otder and confirmation unit twelve contract and bill of lading unit thirteen letter of credit unit fourteen claim and refusal unit fifteen shopping unit sisteen sightseeing unit seventeen seeing the doctor unit eighteen making a telephone call unit nineteen abstract