Required to deal with a wide range of student achievement and behavior; required to remain flexible to meet students immediate needs; required to handle multiple tasks simultaneously and prioritize; may experience frequent interruptions; may occasionally deal with distraught or difficult students; potentially exposed to ordinary infectious diseases carried by students; in some positions the necessary and appropriate instructional methods may require specific positions and movements, and sufficient stamina and exertions, to demonstrate techniques properly for student safety, or to conduct or direct students; in some positions precautions may need to be taken to prevent or lessen exposure of self and/or students to various materials, fumes, equipment, cutting edges or hot surfaces; may teach in a classroom without telephone communication. Specific programs may require additional academic preparation or professional experience, including; working with bilingual students and assisting them in the transition to regular classrooms; implementing programs designed to prevent the dropout of "at risk" students; and, teaching multi-level, open-concept, and main streamed classes.