I could callus you could callus he could callus we could callus you could callus they could callus
V-ing form
I could be callusing you could be callusing he could be callusing we could be callusing you could be callusing they could be callusing
Perfect
I could have callused you could have callused he could have callused we could have callused you could have callused they could have callused
V-ing perfect
I could have been callusing you could have been callusing he could have been callusing we could have been callusing you could have been callusing they could have been callusing
Negation
Simple form
I could not callus you could not callus he could not callus we could not callus you could not callus they could not callus
V-ing form
I could not be callusing you could not be callusing he could not be callusing we could not be callusing you could not be callusing they could not be callusing
Perfect
I could not have callused you could not have callused he could not have callused we could not have callused you could not have callused they could not have callused
V-ing perfect
I could not have been callusing you could not have been callusing he could not have been callusing we could not have been callusing you could not have been callusing they could not have been callusing
Interrogative form
Simple form
could I callus? could you callus? could he callus? could we callus? could you callus? could they callus?
V-ing form
could I be callusing? could you be callusing? could he be callusing? could we be callusing? could you be callusing? could they be callusing?
Perfect
could I have callused? could you have callused? could he have callused? could we have callused? could you have callused? could they have callused?
V-ing perfect
could I have been callusing? could you have been callusing? could he have been callusing? could we have been callusing? could you have been callusing? could they have been callusing?
Interro-negative form
Simple form
could I not callus? could you not callus? could he not callus? could we not callus? could you not callus? could they not callus?
V-ing form
could I not be callusing? could you not be callusing? could he not be callusing? could we not be callusing? could you not be callusing? could they not be callusing?
Perfect
could I not have callused? could you not have callused? could he not have callused? could we not have callused? could you not have callused? could they not have callused?
V-ing perfect
could I not have been callusing? could you not have been callusing? could he not have been callusing? could we not have been callusing? could you not have been callusing? could they not have been callusing?