could slip
Regular verb: slip - slipped- slipped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could slip
you could slip
she could slip
we could slip
you could slip
they could slip 	I could be slipping
you could be slipping
she could be slipping
we could be slipping
you could be slipping
they could be slipping	I could have slipped
you could have slipped
she could have slipped
we could have slipped
you could have slipped
they could have slipped	I could have been slipping
you could have been slipping
she could have been slipping
we could have been slipping
you could have been slipping
they could have been slipping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't slip
you couldn't slip
she couldn't slip
we couldn't slip
you couldn't slip
they couldn't slip 	I couldn't be slipping
you couldn't be slipping
she couldn't be slipping
we couldn't be slipping
you couldn't be slipping
they couldn't be slipping	I couldn't have slipped
you couldn't have slipped
she couldn't have slipped
we couldn't have slipped
you couldn't have slipped
they couldn't have slipped	I couldn't have been slipping
you couldn't have been slipping
she couldn't have been slipping
we couldn't have been slipping
you couldn't have been slipping
they couldn't have been slipping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I slip?
could you slip?
could she slip?
could we slip?
could you slip?
could they slip? 	could I be slipping?
could you be slipping?
could she be slipping?
could we be slipping?
could you be slipping?
could they be slipping? 	could I have slipped?
could you have slipped?
could she have slipped?
could we have slipped?
could you have slipped?
could they have slipped? 	could I have been slipping?
could you have been slipping?
could she have been slipping?
could we have been slipping?
could you have been slipping?
could they have been slipping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I slip?
couldn't you slip?
couldn't she slip?
couldn't we slip?
couldn't you slip?
couldn't they slip? 	couldn't I be slipping?
couldn't you be slipping?
couldn't she be slipping?
couldn't we be slipping?
couldn't you be slipping?
couldn't they be slipping? 	couldn't I have slipped?
couldn't you have slipped?
couldn't she have slipped?
couldn't we have slipped?
couldn't you have slipped?
couldn't they have slipped? 	couldn't I have been slipping?
couldn't you have been slipping?
couldn't she have been slipping?
couldn't we have been slipping?
couldn't you have been slipping?
couldn't they have been slipping?