Question

He has eat breakfast at seven o"clock. 改病句，求高手帮忙！谢谢

Answer 1

He has breakfast at seven o'clock. 或者
He had breakfast at seven o'clock
因为有时间状语 at seven o'clock, 所以不能用现在完成时，如果没有 at seven o'clock.
就可以改成： He has eaten breakfast . 或 He has had breakfast.

Answer 2

have breakfast吃早饭，固定搭配。
he has breakfast at seven o'clock. 表示通常情况
He had breakfast at seven o'clock. 表示过去发生的事
两种均可。

Answer 3

去掉eat。have breakfast吃早饭，固定搭配。
He has breakfast at seven o"clock.