could gnash
Regular verb: gnash - gnashed- gnashed

Affirmation 	
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I could gnash
you could gnash
he could gnash
we could gnash
you could gnash
they could gnash 	I could be gnashing
you could be gnashing
he could be gnashing
we could be gnashing
you could be gnashing
they could be gnashing	I could have gnashed
you could have gnashed
he could have gnashed
we could have gnashed
you could have gnashed
they could have gnashed	I could have been gnashing
you could have been gnashing
he could have been gnashing
we could have been gnashing
you could have been gnashing
they could have been gnashing	

Negation 	
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I couldn't gnash
you couldn't gnash
he couldn't gnash
we couldn't gnash
you couldn't gnash
they couldn't gnash 	I couldn't be gnashing
you couldn't be gnashing
he couldn't be gnashing
we couldn't be gnashing
you couldn't be gnashing
they couldn't be gnashing	I couldn't have gnashed
you couldn't have gnashed
he couldn't have gnashed
we couldn't have gnashed
you couldn't have gnashed
they couldn't have gnashed	I couldn't have been gnashing
you couldn't have been gnashing
he couldn't have been gnashing
we couldn't have been gnashing
you couldn't have been gnashing
they couldn't have been gnashing	

Interrogative form 	
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could I gnash?
could you gnash?
could he gnash?
could we gnash?
could you gnash?
could they gnash? 	could I be gnashing?
could you be gnashing?
could he be gnashing?
could we be gnashing?
could you be gnashing?
could they be gnashing? 	could I have gnashed?
could you have gnashed?
could he have gnashed?
could we have gnashed?
could you have gnashed?
could they have gnashed? 	could I have been gnashing?
could you have been gnashing?
could he have been gnashing?
could we have been gnashing?
could you have been gnashing?
could they have been gnashing? 	

Interro-negative form 	
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couldn't I gnash?
couldn't you gnash?
couldn't he gnash?
couldn't we gnash?
couldn't you gnash?
couldn't they gnash? 	couldn't I be gnashing?
couldn't you be gnashing?
couldn't he be gnashing?
couldn't we be gnashing?
couldn't you be gnashing?
couldn't they be gnashing? 	couldn't I have gnashed?
couldn't you have gnashed?
couldn't he have gnashed?
couldn't we have gnashed?
couldn't you have gnashed?
couldn't they have gnashed? 	couldn't I have been gnashing?
couldn't you have been gnashing?
couldn't he have been gnashing?
couldn't we have been gnashing?
couldn't you have been gnashing?
couldn't they have been gnashing?