staple cereal

例句：

1. 1.The staple of the diet is rice.
   饮食的主食是米饭。
2. 2. He prefers to eat cereal for breakfast every day.
   他每天早餐喜欢吃麦片。
3. 3.The grains are used as a staple food in many parts of the world.
   这些谷物在世界许多地方被用作主食。