could backsolve
Regular verb: backsolve - backsolved- backsolved

Affirmation 	
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I could backsolve
you could backsolve
he could backsolve
we could backsolve
you could backsolve
they could backsolve 	I could be backsolving
you could be backsolving
he could be backsolving
we could be backsolving
you could be backsolving
they could be backsolving	I could have backsolved
you could have backsolved
he could have backsolved
we could have backsolved
you could have backsolved
they could have backsolved	I could have been backsolving
you could have been backsolving
he could have been backsolving
we could have been backsolving
you could have been backsolving
they could have been backsolving	

Negation 	
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I couldn't backsolve
you couldn't backsolve
he couldn't backsolve
we couldn't backsolve
you couldn't backsolve
they couldn't backsolve 	I couldn't be backsolving
you couldn't be backsolving
he couldn't be backsolving
we couldn't be backsolving
you couldn't be backsolving
they couldn't be backsolving	I couldn't have backsolved
you couldn't have backsolved
he couldn't have backsolved
we couldn't have backsolved
you couldn't have backsolved
they couldn't have backsolved	I couldn't have been backsolving
you couldn't have been backsolving
he couldn't have been backsolving
we couldn't have been backsolving
you couldn't have been backsolving
they couldn't have been backsolving	

Interrogative form 	
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could I backsolve?
could you backsolve?
could he backsolve?
could we backsolve?
could you backsolve?
could they backsolve? 	could I be backsolving?
could you be backsolving?
could he be backsolving?
could we be backsolving?
could you be backsolving?
could they be backsolving? 	could I have backsolved?
could you have backsolved?
could he have backsolved?
could we have backsolved?
could you have backsolved?
could they have backsolved? 	could I have been backsolving?
could you have been backsolving?
could he have been backsolving?
could we have been backsolving?
could you have been backsolving?
could they have been backsolving? 	

Interro-negative form 	
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couldn't I backsolve?
couldn't you backsolve?
couldn't he backsolve?
couldn't we backsolve?
couldn't you backsolve?
couldn't they backsolve? 	couldn't I be backsolving?
couldn't you be backsolving?
couldn't he be backsolving?
couldn't we be backsolving?
couldn't you be backsolving?
couldn't they be backsolving? 	couldn't I have backsolved?
couldn't you have backsolved?
couldn't he have backsolved?
couldn't we have backsolved?
couldn't you have backsolved?
couldn't they have backsolved? 	couldn't I have been backsolving?
couldn't you have been backsolving?
couldn't he have been backsolving?
couldn't we have been backsolving?
couldn't you have been backsolving?
couldn't they have been backsolving?