I can modulate you can modulate he can modulate we can modulate you can modulate they can modulate
V-ing form
I can be modulating you can be modulating he can be modulating we can be modulating you can be modulating they can be modulating
Perfect
I can have modulated you can have modulated he can have modulated we can have modulated you can have modulated they can have modulated
V-ing perfect
I can have been modulating you can have been modulating he can have been modulating we can have been modulating you can have been modulating they can have been modulating
Negation
Simple form
I can't modulate you can't modulate he can't modulate we can't modulate you can't modulate they can't modulate
V-ing form
I can't be modulating you can't be modulating he can't be modulating we can't be modulating you can't be modulating they can't be modulating
Perfect
I can't have modulated you can't have modulated he can't have modulated we can't have modulated you can't have modulated they can't have modulated
V-ing perfect
I can't have been modulating you can't have been modulating he can't have been modulating we can't have been modulating you can't have been modulating they can't have been modulating
Interrogative form
Simple form
can I modulate? can you modulate? can he modulate? can we modulate? can you modulate? can they modulate?
V-ing form
can I be modulating? can you be modulating? can he be modulating? can we be modulating? can you be modulating? can they be modulating?
Perfect
can I have modulated? can you have modulated? can he have modulated? can we have modulated? can you have modulated? can they have modulated?
V-ing perfect
can I have been modulating? can you have been modulating? can he have been modulating? can we have been modulating? can you have been modulating? can they have been modulating?
Interro-negative form
Simple form
can't I modulate? can't you modulate? can't he modulate? can't we modulate? can't you modulate? can't they modulate?
V-ing form
can't I be modulating? can't you be modulating? can't he be modulating? can't we be modulating? can't you be modulating? can't they be modulating?
Perfect
can't I have modulated? can't you have modulated? can't he have modulated? can't we have modulated? can't you have modulated? can't they have modulated?
V-ing perfect
can't I have been modulating? can't you have been modulating? can't he have been modulating? can't we have been modulating? can't you have been modulating? can't they have been modulating?