I want to be a model student. What shall I do?
　　I should be polite. I should study hard. I should capful and helpful. I should walk in the corridors. I should throw rubbish in the bin. I should be quiet in the library. I shouldn”t walk and run on the grass. I shouldn”t throw rubbish on the floor. I shouldn”t run in the corridors. I shouldn”t fight. I shouldn”t be noisy in the library.