could shield
Regular verb: shield - shielded- shielded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could shield
you could shield
he could shield
we could shield
you could shield
they could shield 	I could be shielding
you could be shielding
he could be shielding
we could be shielding
you could be shielding
they could be shielding	I could have shielded
you could have shielded
he could have shielded
we could have shielded
you could have shielded
they could have shielded	I could have been shielding
you could have been shielding
he could have been shielding
we could have been shielding
you could have been shielding
they could have been shielding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not shield
you could not shield
he could not shield
we could not shield
you could not shield
they could not shield 	I could not be shielding
you could not be shielding
he could not be shielding
we could not be shielding
you could not be shielding
they could not be shielding	I could not have shielded
you could not have shielded
he could not have shielded
we could not have shielded
you could not have shielded
they could not have shielded	I could not have been shielding
you could not have been shielding
he could not have been shielding
we could not have been shielding
you could not have been shielding
they could not have been shielding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I shield?
could you shield?
could he shield?
could we shield?
could you shield?
could they shield? 	could I be shielding?
could you be shielding?
could he be shielding?
could we be shielding?
could you be shielding?
could they be shielding? 	could I have shielded?
could you have shielded?
could he have shielded?
could we have shielded?
could you have shielded?
could they have shielded? 	could I have been shielding?
could you have been shielding?
could he have been shielding?
could we have been shielding?
could you have been shielding?
could they have been shielding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not shield?
could you not shield?
could he not shield?
could we not shield?
could you not shield?
could they not shield? 	could I not be shielding?
could you not be shielding?
could he not be shielding?
could we not be shielding?
could you not be shielding?
could they not be shielding? 	could I not have shielded?
could you not have shielded?
could he not have shielded?
could we not have shielded?
could you not have shielded?
could they not have shielded? 	could I not have been shielding?
could you not have been shielding?
could he not have been shielding?
could we not have been shielding?
could you not have been shielding?
could they not have been shielding?