could japan
Regular verb: japan - japaned- japaned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could japan
you could japan
he could japan
we could japan
you could japan
they could japan 	I could be japaning
you could be japaning
he could be japaning
we could be japaning
you could be japaning
they could be japaning	I could have japaned
you could have japaned
he could have japaned
we could have japaned
you could have japaned
they could have japaned	I could have been japaning
you could have been japaning
he could have been japaning
we could have been japaning
you could have been japaning
they could have been japaning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't japan
you couldn't japan
he couldn't japan
we couldn't japan
you couldn't japan
they couldn't japan 	I couldn't be japaning
you couldn't be japaning
he couldn't be japaning
we couldn't be japaning
you couldn't be japaning
they couldn't be japaning	I couldn't have japaned
you couldn't have japaned
he couldn't have japaned
we couldn't have japaned
you couldn't have japaned
they couldn't have japaned	I couldn't have been japaning
you couldn't have been japaning
he couldn't have been japaning
we couldn't have been japaning
you couldn't have been japaning
they couldn't have been japaning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I japan?
could you japan?
could he japan?
could we japan?
could you japan?
could they japan? 	could I be japaning?
could you be japaning?
could he be japaning?
could we be japaning?
could you be japaning?
could they be japaning? 	could I have japaned?
could you have japaned?
could he have japaned?
could we have japaned?
could you have japaned?
could they have japaned? 	could I have been japaning?
could you have been japaning?
could he have been japaning?
could we have been japaning?
could you have been japaning?
could they have been japaning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I japan?
couldn't you japan?
couldn't he japan?
couldn't we japan?
couldn't you japan?
couldn't they japan? 	couldn't I be japaning?
couldn't you be japaning?
couldn't he be japaning?
couldn't we be japaning?
couldn't you be japaning?
couldn't they be japaning? 	couldn't I have japaned?
couldn't you have japaned?
couldn't he have japaned?
couldn't we have japaned?
couldn't you have japaned?
couldn't they have japaned? 	couldn't I have been japaning?
couldn't you have been japaning?
couldn't he have been japaning?
couldn't we have been japaning?
couldn't you have been japaning?
couldn't they have been japaning?