We usually have lunch at school.A. the B. a C. /

问题补充：

We usually have lunch at school.

A. the B. a C. /

答案：

解析：考察冠词。句意：我们通常在校吃午饭。Lunch在此处表示抽象含义，不可数，泛指不用冠词，不加任何冠词。故选C。