cereal意思是麦片粥时，是不可数的。表示谷类植物、谷物时，是可数的。例如，Wheat and rice are cereals.小麦和水稻是谷类植物。
意思是谷类食物；麦片粥
breakfast cereals 早餐用的谷类食品
意思是谷类食物时，可数
a bowl of cereal 一碗麦片粥
意思是麦片粥，不可数
cereal例句1.有变体名词
Cereal or breakfast cereal is a food made from grain.
It is mixed with milk and eaten for breakfast.
I have a bowl of cereal every morning.
2.可数名词
Cereals are plants such as wheat，corn，or rice that produce grain.
...the rich cereal-growing districts of the Paris Basin.
