阅读下面材料,在空白处填入适当的内容(1个单词$或括号内单词的正确形式。
Last week,our class was on duty in the cafeteria. On the first day,I was shocked to see so much leftover food      (throw) away by students. What    waste! Being concerned about it,my classmates and I had a heated discussion on how     (solve) the problem. Lots of good ideas came up,such as holding class meetings,putting up a wall newspaper and charging a fine for wasting food.      (final),we all agreed that putting up a wall news­paper would be a good      (choose).
The next day, we put our idea into reality. Towards lunch time, we put up a wall newspaper outside the school cafeteria,     (call) on students not to waste food. Many students gathered around to read and express their support.     my great delight, there were chan­ges soon. In the cafeteria, I    (find) the plates returned after lunch all empty without any leftover. Food     (save) and the dining hall was cleaner. Seeing this, I felt proud of     we had done.