Present Simple: Does dad buy a big car?Past Simple: Did dad buy a big car?Present Continuous: Is dad buying a big car?Future Simple: Will dad buy a big car?
In the past:
Present Simple: Did dad buy a big car?Past Simple: Had dad bought a big car?Present Continuous: Was dad buying a big car?Future Simple: Would dad buy a big car?Present Perfect: Has dad bought a big car?
In the past:
Present Simple: Did dad buy a big car?Past Simple: Had dad bought a big car?Present Continuous: Was dad buying a big car?Future Simple: Would dad buy a big car?Present Perfect: Has dad bought a big car?