As an old saying goes, bread is the staff of life. There is such a huge population in the worldthat it is really important to keep the food enough.But it is a fact that there is more land of urban planning while there is less land for growing crops. Therefore a lack of food has been a serious problem.So saving food,saving the wordIt’s a good idea to ….. It’s time for sb to do sth It’s one’s duty to do sth