We have breakfast seven o’clock morning.A. the; in atB. /; at in theC. the; in in the

问题补充：

We have breakfast seven o’clock morning.

A. the; in, at

B. /; at, in the

C. the; in, in the

D. /; on, in

答案：

A. the; in, at

(答案→)B. /; at, in the

C. the; in, in the

D. /; on, in

解析：在表示时间时,in表示在一个时间范围或者接一段时间,表示多久之后;at表示在具体时刻;on表示在具体某一天. 句意:我们在早晨七点钟吃早饭. 本句中的早饭表示抽象含义,泛指,故不加冠词. 结合语境可知选B.