could slither
Regular verb: slither - slithered- slithered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could slither
you could slither
he could slither
we could slither
you could slither
they could slither 	I could be slithering
you could be slithering
he could be slithering
we could be slithering
you could be slithering
they could be slithering	I could have slithered
you could have slithered
he could have slithered
we could have slithered
you could have slithered
they could have slithered	I could have been slithering
you could have been slithering
he could have been slithering
we could have been slithering
you could have been slithering
they could have been slithering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't slither
you couldn't slither
he couldn't slither
we couldn't slither
you couldn't slither
they couldn't slither 	I couldn't be slithering
you couldn't be slithering
he couldn't be slithering
we couldn't be slithering
you couldn't be slithering
they couldn't be slithering	I couldn't have slithered
you couldn't have slithered
he couldn't have slithered
we couldn't have slithered
you couldn't have slithered
they couldn't have slithered	I couldn't have been slithering
you couldn't have been slithering
he couldn't have been slithering
we couldn't have been slithering
you couldn't have been slithering
they couldn't have been slithering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I slither?
could you slither?
could he slither?
could we slither?
could you slither?
could they slither? 	could I be slithering?
could you be slithering?
could he be slithering?
could we be slithering?
could you be slithering?
could they be slithering? 	could I have slithered?
could you have slithered?
could he have slithered?
could we have slithered?
could you have slithered?
could they have slithered? 	could I have been slithering?
could you have been slithering?
could he have been slithering?
could we have been slithering?
could you have been slithering?
could they have been slithering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I slither?
couldn't you slither?
couldn't he slither?
couldn't we slither?
couldn't you slither?
couldn't they slither? 	couldn't I be slithering?
couldn't you be slithering?
couldn't he be slithering?
couldn't we be slithering?
couldn't you be slithering?
couldn't they be slithering? 	couldn't I have slithered?
couldn't you have slithered?
couldn't he have slithered?
couldn't we have slithered?
couldn't you have slithered?
couldn't they have slithered? 	couldn't I have been slithering?
couldn't you have been slithering?
couldn't he have been slithering?
couldn't we have been slithering?
couldn't you have been slithering?
couldn't they have been slithering?