I could dust you could dust she could dust we could dust you could dust they could dust
V-ing form
I could be dusting you could be dusting she could be dusting we could be dusting you could be dusting they could be dusting
Perfect
I could have dusted you could have dusted she could have dusted we could have dusted you could have dusted they could have dusted
V-ing perfect
I could have been dusting you could have been dusting she could have been dusting we could have been dusting you could have been dusting they could have been dusting
Negation
Simple form
I could not dust you could not dust she could not dust we could not dust you could not dust they could not dust
V-ing form
I could not be dusting you could not be dusting she could not be dusting we could not be dusting you could not be dusting they could not be dusting
Perfect
I could not have dusted you could not have dusted she could not have dusted we could not have dusted you could not have dusted they could not have dusted
V-ing perfect
I could not have been dusting you could not have been dusting she could not have been dusting we could not have been dusting you could not have been dusting they could not have been dusting
Interrogative form
Simple form
could I dust? could you dust? could she dust? could we dust? could you dust? could they dust?
V-ing form
could I be dusting? could you be dusting? could she be dusting? could we be dusting? could you be dusting? could they be dusting?
Perfect
could I have dusted? could you have dusted? could she have dusted? could we have dusted? could you have dusted? could they have dusted?
V-ing perfect
could I have been dusting? could you have been dusting? could she have been dusting? could we have been dusting? could you have been dusting? could they have been dusting?
Interro-negative form
Simple form
could I not dust? could you not dust? could she not dust? could we not dust? could you not dust? could they not dust?
V-ing form
could I not be dusting? could you not be dusting? could she not be dusting? could we not be dusting? could you not be dusting? could they not be dusting?
Perfect
could I not have dusted? could you not have dusted? could she not have dusted? could we not have dusted? could you not have dusted? could they not have dusted?
V-ing perfect
could I not have been dusting? could you not have been dusting? could she not have been dusting? could we not have been dusting? could you not have been dusting? could they not have been dusting?