开头：we have had a heated discussion about whether we should take snacks into classroom.different students have different opinions.
中间：some hold the view that we should take snacks.on one hand,we may feel hungry after studying,so the snacks can let us energetic.on the other hand,snacks can relax ourselves when we are tired.however,others think differently.(然后例举反面观点)
结尾：as far as I am concerned,(给出个人观点,我觉得应该是不同意带零食好)