could understock
Regular verb: understock - understocked- understocked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could understock
you could understock
he could understock
we could understock
you could understock
they could understock 	I could be understocking
you could be understocking
he could be understocking
we could be understocking
you could be understocking
they could be understocking	I could have understocked
you could have understocked
he could have understocked
we could have understocked
you could have understocked
they could have understocked	I could have been understocking
you could have been understocking
he could have been understocking
we could have been understocking
you could have been understocking
they could have been understocking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't understock
you couldn't understock
he couldn't understock
we couldn't understock
you couldn't understock
they couldn't understock 	I couldn't be understocking
you couldn't be understocking
he couldn't be understocking
we couldn't be understocking
you couldn't be understocking
they couldn't be understocking	I couldn't have understocked
you couldn't have understocked
he couldn't have understocked
we couldn't have understocked
you couldn't have understocked
they couldn't have understocked	I couldn't have been understocking
you couldn't have been understocking
he couldn't have been understocking
we couldn't have been understocking
you couldn't have been understocking
they couldn't have been understocking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I understock?
could you understock?
could he understock?
could we understock?
could you understock?
could they understock? 	could I be understocking?
could you be understocking?
could he be understocking?
could we be understocking?
could you be understocking?
could they be understocking? 	could I have understocked?
could you have understocked?
could he have understocked?
could we have understocked?
could you have understocked?
could they have understocked? 	could I have been understocking?
could you have been understocking?
could he have been understocking?
could we have been understocking?
could you have been understocking?
could they have been understocking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I understock?
couldn't you understock?
couldn't he understock?
couldn't we understock?
couldn't you understock?
couldn't they understock? 	couldn't I be understocking?
couldn't you be understocking?
couldn't he be understocking?
couldn't we be understocking?
couldn't you be understocking?
couldn't they be understocking? 	couldn't I have understocked?
couldn't you have understocked?
couldn't he have understocked?
couldn't we have understocked?
couldn't you have understocked?
couldn't they have understocked? 	couldn't I have been understocking?
couldn't you have been understocking?
couldn't he have been understocking?
couldn't we have been understocking?
couldn't you have been understocking?
couldn't they have been understocking?