could climb
Regular verb: climb - climbed- climbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could climb
you could climb
he could climb
we could climb
you could climb
they could climb 	I could be climbing
you could be climbing
he could be climbing
we could be climbing
you could be climbing
they could be climbing	I could have climbed
you could have climbed
he could have climbed
we could have climbed
you could have climbed
they could have climbed	I could have been climbing
you could have been climbing
he could have been climbing
we could have been climbing
you could have been climbing
they could have been climbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not climb
you could not climb
he could not climb
we could not climb
you could not climb
they could not climb 	I could not be climbing
you could not be climbing
he could not be climbing
we could not be climbing
you could not be climbing
they could not be climbing	I could not have climbed
you could not have climbed
he could not have climbed
we could not have climbed
you could not have climbed
they could not have climbed	I could not have been climbing
you could not have been climbing
he could not have been climbing
we could not have been climbing
you could not have been climbing
they could not have been climbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I climb?
could you climb?
could he climb?
could we climb?
could you climb?
could they climb? 	could I be climbing?
could you be climbing?
could he be climbing?
could we be climbing?
could you be climbing?
could they be climbing? 	could I have climbed?
could you have climbed?
could he have climbed?
could we have climbed?
could you have climbed?
could they have climbed? 	could I have been climbing?
could you have been climbing?
could he have been climbing?
could we have been climbing?
could you have been climbing?
could they have been climbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not climb?
could you not climb?
could he not climb?
could we not climb?
could you not climb?
could they not climb? 	could I not be climbing?
could you not be climbing?
could he not be climbing?
could we not be climbing?
could you not be climbing?
could they not be climbing? 	could I not have climbed?
could you not have climbed?
could he not have climbed?
could we not have climbed?
could you not have climbed?
could they not have climbed? 	could I not have been climbing?
could you not have been climbing?
could he not have been climbing?
could we not have been climbing?
could you not have been climbing?
could they not have been climbing?