do you have breakfast at 6.30 ?

`*` Do you have breakfast at 6.30 ?

$\rightarrow$ Yes, I do

$\rightarrow$ No, I don't

Câu trúc : Yes/No question : 

`-` Do/Does + S + V + (O)[Thì HTĐ thể Interrogative Sentences]

$\rightarrow$ Yes, S + do/does

$\rightarrow$ No, S + don't/doesn't