could protect
Regular verb: protect - protected- protected

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could protect
you could protect
she could protect
we could protect
you could protect
they could protect 	I could be protecting
you could be protecting
she could be protecting
we could be protecting
you could be protecting
they could be protecting	I could have protected
you could have protected
she could have protected
we could have protected
you could have protected
they could have protected	I could have been protecting
you could have been protecting
she could have been protecting
we could have been protecting
you could have been protecting
they could have been protecting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't protect
you couldn't protect
she couldn't protect
we couldn't protect
you couldn't protect
they couldn't protect 	I couldn't be protecting
you couldn't be protecting
she couldn't be protecting
we couldn't be protecting
you couldn't be protecting
they couldn't be protecting	I couldn't have protected
you couldn't have protected
she couldn't have protected
we couldn't have protected
you couldn't have protected
they couldn't have protected	I couldn't have been protecting
you couldn't have been protecting
she couldn't have been protecting
we couldn't have been protecting
you couldn't have been protecting
they couldn't have been protecting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I protect?
could you protect?
could she protect?
could we protect?
could you protect?
could they protect? 	could I be protecting?
could you be protecting?
could she be protecting?
could we be protecting?
could you be protecting?
could they be protecting? 	could I have protected?
could you have protected?
could she have protected?
could we have protected?
could you have protected?
could they have protected? 	could I have been protecting?
could you have been protecting?
could she have been protecting?
could we have been protecting?
could you have been protecting?
could they have been protecting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I protect?
couldn't you protect?
couldn't she protect?
couldn't we protect?
couldn't you protect?
couldn't they protect? 	couldn't I be protecting?
couldn't you be protecting?
couldn't she be protecting?
couldn't we be protecting?
couldn't you be protecting?
couldn't they be protecting? 	couldn't I have protected?
couldn't you have protected?
couldn't she have protected?
couldn't we have protected?
couldn't you have protected?
couldn't they have protected? 	couldn't I have been protecting?
couldn't you have been protecting?
couldn't she have been protecting?
couldn't we have been protecting?
couldn't you have been protecting?
couldn't they have been protecting?