could stall
Regular verb: stall - stalled- stalled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could stall
you could stall
he could stall
we could stall
you could stall
they could stall 	I could be stalling
you could be stalling
he could be stalling
we could be stalling
you could be stalling
they could be stalling	I could have stalled
you could have stalled
he could have stalled
we could have stalled
you could have stalled
they could have stalled	I could have been stalling
you could have been stalling
he could have been stalling
we could have been stalling
you could have been stalling
they could have been stalling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not stall
you could not stall
he could not stall
we could not stall
you could not stall
they could not stall 	I could not be stalling
you could not be stalling
he could not be stalling
we could not be stalling
you could not be stalling
they could not be stalling	I could not have stalled
you could not have stalled
he could not have stalled
we could not have stalled
you could not have stalled
they could not have stalled	I could not have been stalling
you could not have been stalling
he could not have been stalling
we could not have been stalling
you could not have been stalling
they could not have been stalling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I stall?
could you stall?
could he stall?
could we stall?
could you stall?
could they stall? 	could I be stalling?
could you be stalling?
could he be stalling?
could we be stalling?
could you be stalling?
could they be stalling? 	could I have stalled?
could you have stalled?
could he have stalled?
could we have stalled?
could you have stalled?
could they have stalled? 	could I have been stalling?
could you have been stalling?
could he have been stalling?
could we have been stalling?
could you have been stalling?
could they have been stalling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not stall?
could you not stall?
could he not stall?
could we not stall?
could you not stall?
could they not stall? 	could I not be stalling?
could you not be stalling?
could he not be stalling?
could we not be stalling?
could you not be stalling?
could they not be stalling? 	could I not have stalled?
could you not have stalled?
could he not have stalled?
could we not have stalled?
could you not have stalled?
could they not have stalled? 	could I not have been stalling?
could you not have been stalling?
could he not have been stalling?
could we not have been stalling?
could you not have been stalling?
could they not have been stalling?