could block
Regular verb: block - blocked- blocked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could block
you could block
he could block
we could block
you could block
they could block 	I could be blocking
you could be blocking
he could be blocking
we could be blocking
you could be blocking
they could be blocking	I could have blocked
you could have blocked
he could have blocked
we could have blocked
you could have blocked
they could have blocked	I could have been blocking
you could have been blocking
he could have been blocking
we could have been blocking
you could have been blocking
they could have been blocking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't block
you couldn't block
he couldn't block
we couldn't block
you couldn't block
they couldn't block 	I couldn't be blocking
you couldn't be blocking
he couldn't be blocking
we couldn't be blocking
you couldn't be blocking
they couldn't be blocking	I couldn't have blocked
you couldn't have blocked
he couldn't have blocked
we couldn't have blocked
you couldn't have blocked
they couldn't have blocked	I couldn't have been blocking
you couldn't have been blocking
he couldn't have been blocking
we couldn't have been blocking
you couldn't have been blocking
they couldn't have been blocking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I block?
could you block?
could he block?
could we block?
could you block?
could they block? 	could I be blocking?
could you be blocking?
could he be blocking?
could we be blocking?
could you be blocking?
could they be blocking? 	could I have blocked?
could you have blocked?
could he have blocked?
could we have blocked?
could you have blocked?
could they have blocked? 	could I have been blocking?
could you have been blocking?
could he have been blocking?
could we have been blocking?
could you have been blocking?
could they have been blocking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I block?
couldn't you block?
couldn't he block?
couldn't we block?
couldn't you block?
couldn't they block? 	couldn't I be blocking?
couldn't you be blocking?
couldn't he be blocking?
couldn't we be blocking?
couldn't you be blocking?
couldn't they be blocking? 	couldn't I have blocked?
couldn't you have blocked?
couldn't he have blocked?
couldn't we have blocked?
couldn't you have blocked?
couldn't they have blocked? 	couldn't I have been blocking?
couldn't you have been blocking?
couldn't he have been blocking?
couldn't we have been blocking?
couldn't you have been blocking?
couldn't they have been blocking?