iron rations       
noun [ plural ]  old-fashioned uk/ˌaɪən ˈræʃ.ənz/ us/ˌaɪrn ˈræʃ.ənz/
 基本口粮
a basic amount of food for a person to live on
  The hotel food was dreadful, so for three days we were on iron rations of fruit, cheese, and bread. 旅馆里的食物糟透了,所以连续3天我们只吃些水果、奶酪和面包充饥。