shortfall       
noun [ C ] uk/ˈʃɔːt.fɔːl/ us/ˈʃɔːrt.fɑːl/
 不足之数;缺口;差额
an amount that is less than the level that was expected or needed
  The drought caused serious shortfalls in the food supply. 干旱造成了严重的食品供应短缺。 
 Opposites: glut oversupplysurfeit 
Compare: deficit