could countercheck
Regular verb: countercheck - counterchecked- counterchecked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could countercheck
you could countercheck
he could countercheck
we could countercheck
you could countercheck
they could countercheck 	I could be counterchecking
you could be counterchecking
he could be counterchecking
we could be counterchecking
you could be counterchecking
they could be counterchecking	I could have counterchecked
you could have counterchecked
he could have counterchecked
we could have counterchecked
you could have counterchecked
they could have counterchecked	I could have been counterchecking
you could have been counterchecking
he could have been counterchecking
we could have been counterchecking
you could have been counterchecking
they could have been counterchecking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't countercheck
you couldn't countercheck
he couldn't countercheck
we couldn't countercheck
you couldn't countercheck
they couldn't countercheck 	I couldn't be counterchecking
you couldn't be counterchecking
he couldn't be counterchecking
we couldn't be counterchecking
you couldn't be counterchecking
they couldn't be counterchecking	I couldn't have counterchecked
you couldn't have counterchecked
he couldn't have counterchecked
we couldn't have counterchecked
you couldn't have counterchecked
they couldn't have counterchecked	I couldn't have been counterchecking
you couldn't have been counterchecking
he couldn't have been counterchecking
we couldn't have been counterchecking
you couldn't have been counterchecking
they couldn't have been counterchecking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I countercheck?
could you countercheck?
could he countercheck?
could we countercheck?
could you countercheck?
could they countercheck? 	could I be counterchecking?
could you be counterchecking?
could he be counterchecking?
could we be counterchecking?
could you be counterchecking?
could they be counterchecking? 	could I have counterchecked?
could you have counterchecked?
could he have counterchecked?
could we have counterchecked?
could you have counterchecked?
could they have counterchecked? 	could I have been counterchecking?
could you have been counterchecking?
could he have been counterchecking?
could we have been counterchecking?
could you have been counterchecking?
could they have been counterchecking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I countercheck?
couldn't you countercheck?
couldn't he countercheck?
couldn't we countercheck?
couldn't you countercheck?
couldn't they countercheck? 	couldn't I be counterchecking?
couldn't you be counterchecking?
couldn't he be counterchecking?
couldn't we be counterchecking?
couldn't you be counterchecking?
couldn't they be counterchecking? 	couldn't I have counterchecked?
couldn't you have counterchecked?
couldn't he have counterchecked?
couldn't we have counterchecked?
couldn't you have counterchecked?
couldn't they have counterchecked? 	couldn't I have been counterchecking?
couldn't you have been counterchecking?
couldn't he have been counterchecking?
couldn't we have been counterchecking?
couldn't you have been counterchecking?
couldn't they have been counterchecking?