could shift
Regular verb: shift - shifted- shifted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could shift
you could shift
she could shift
we could shift
you could shift
they could shift 	I could be shifting
you could be shifting
she could be shifting
we could be shifting
you could be shifting
they could be shifting	I could have shifted
you could have shifted
she could have shifted
we could have shifted
you could have shifted
they could have shifted	I could have been shifting
you could have been shifting
she could have been shifting
we could have been shifting
you could have been shifting
they could have been shifting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not shift
you could not shift
she could not shift
we could not shift
you could not shift
they could not shift 	I could not be shifting
you could not be shifting
she could not be shifting
we could not be shifting
you could not be shifting
they could not be shifting	I could not have shifted
you could not have shifted
she could not have shifted
we could not have shifted
you could not have shifted
they could not have shifted	I could not have been shifting
you could not have been shifting
she could not have been shifting
we could not have been shifting
you could not have been shifting
they could not have been shifting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I shift?
could you shift?
could she shift?
could we shift?
could you shift?
could they shift? 	could I be shifting?
could you be shifting?
could she be shifting?
could we be shifting?
could you be shifting?
could they be shifting? 	could I have shifted?
could you have shifted?
could she have shifted?
could we have shifted?
could you have shifted?
could they have shifted? 	could I have been shifting?
could you have been shifting?
could she have been shifting?
could we have been shifting?
could you have been shifting?
could they have been shifting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not shift?
could you not shift?
could she not shift?
could we not shift?
could you not shift?
could they not shift? 	could I not be shifting?
could you not be shifting?
could she not be shifting?
could we not be shifting?
could you not be shifting?
could they not be shifting? 	could I not have shifted?
could you not have shifted?
could she not have shifted?
could we not have shifted?
could you not have shifted?
could they not have shifted? 	could I not have been shifting?
could you not have been shifting?
could she not have been shifting?
could we not have been shifting?
could you not have been shifting?
could they not have been shifting?