could yock
Regular verb: yock - yocked- yocked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could yock
you could yock
he could yock
we could yock
you could yock
they could yock 	I could be yocking
you could be yocking
he could be yocking
we could be yocking
you could be yocking
they could be yocking	I could have yocked
you could have yocked
he could have yocked
we could have yocked
you could have yocked
they could have yocked	I could have been yocking
you could have been yocking
he could have been yocking
we could have been yocking
you could have been yocking
they could have been yocking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't yock
you couldn't yock
he couldn't yock
we couldn't yock
you couldn't yock
they couldn't yock 	I couldn't be yocking
you couldn't be yocking
he couldn't be yocking
we couldn't be yocking
you couldn't be yocking
they couldn't be yocking	I couldn't have yocked
you couldn't have yocked
he couldn't have yocked
we couldn't have yocked
you couldn't have yocked
they couldn't have yocked	I couldn't have been yocking
you couldn't have been yocking
he couldn't have been yocking
we couldn't have been yocking
you couldn't have been yocking
they couldn't have been yocking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I yock?
could you yock?
could he yock?
could we yock?
could you yock?
could they yock? 	could I be yocking?
could you be yocking?
could he be yocking?
could we be yocking?
could you be yocking?
could they be yocking? 	could I have yocked?
could you have yocked?
could he have yocked?
could we have yocked?
could you have yocked?
could they have yocked? 	could I have been yocking?
could you have been yocking?
could he have been yocking?
could we have been yocking?
could you have been yocking?
could they have been yocking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I yock?
couldn't you yock?
couldn't he yock?
couldn't we yock?
couldn't you yock?
couldn't they yock? 	couldn't I be yocking?
couldn't you be yocking?
couldn't he be yocking?
couldn't we be yocking?
couldn't you be yocking?
couldn't they be yocking? 	couldn't I have yocked?
couldn't you have yocked?
couldn't he have yocked?
couldn't we have yocked?
couldn't you have yocked?
couldn't they have yocked? 	couldn't I have been yocking?
couldn't you have been yocking?
couldn't he have been yocking?
couldn't we have been yocking?
couldn't you have been yocking?
couldn't they have been yocking?