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 couldn't shield
you couldn't shield
he couldn't shield
we couldn't shield
you couldn't shield
they couldn't shield 	I couldn't be shielding
you couldn't be shielding
he couldn't be shielding
we couldn't be shielding
you couldn't be shielding
they couldn't be shielding	I couldn't have shielded
you couldn't have shielded
he couldn't have shielded
we couldn't have shielded
you couldn't have shielded
they couldn't have shielded	I couldn't have been shielding
you couldn't have been shielding
he couldn't have been shielding
we couldn't have been shielding
you couldn't have been shielding
they couldn't 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 	
couldn't I shield?
couldn't you shield?
couldn't he shield?
couldn't we shield?
couldn't you shield?
couldn't they shield? 	couldn't I be shielding?
couldn't you be shielding?
couldn't he be shielding?
couldn't we be shielding?
couldn't you be shielding?
couldn't they be shielding? 	couldn't I have shielded?
couldn't you have shielded?
couldn't he have shielded?
couldn't we have shielded?
couldn't you have shielded?
couldn't they have shielded? 	couldn't I have been shielding?
couldn't you have been shielding?
couldn't he have been shielding?
couldn't we have been shielding?
couldn't you have been shielding?
couldn't they have been shielding?