could prebill
Regular verb: prebill - prebilled- prebilled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could prebill
you could prebill
he could prebill
we could prebill
you could prebill
they could prebill 	I could be prebilling
you could be prebilling
he could be prebilling
we could be prebilling
you could be prebilling
they could be prebilling	I could have prebilled
you could have prebilled
he could have prebilled
we could have prebilled
you could have prebilled
they could have prebilled	I could have been prebilling
you could have been prebilling
he could have been prebilling
we could have been prebilling
you could have been prebilling
they could have been prebilling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't prebill
you couldn't prebill
he couldn't prebill
we couldn't prebill
you couldn't prebill
they couldn't prebill 	I couldn't be prebilling
you couldn't be prebilling
he couldn't be prebilling
we couldn't be prebilling
you couldn't be prebilling
they couldn't be prebilling	I couldn't have prebilled
you couldn't have prebilled
he couldn't have prebilled
we couldn't have prebilled
you couldn't have prebilled
they couldn't have prebilled	I couldn't have been prebilling
you couldn't have been prebilling
he couldn't have been prebilling
we couldn't have been prebilling
you couldn't have been prebilling
they couldn't have been prebilling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I prebill?
could you prebill?
could he prebill?
could we prebill?
could you prebill?
could they prebill? 	could I be prebilling?
could you be prebilling?
could he be prebilling?
could we be prebilling?
could you be prebilling?
could they be prebilling? 	could I have prebilled?
could you have prebilled?
could he have prebilled?
could we have prebilled?
could you have prebilled?
could they have prebilled? 	could I have been prebilling?
could you have been prebilling?
could he have been prebilling?
could we have been prebilling?
could you have been prebilling?
could they have been prebilling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I prebill?
couldn't you prebill?
couldn't he prebill?
couldn't we prebill?
couldn't you prebill?
couldn't they prebill? 	couldn't I be prebilling?
couldn't you be prebilling?
couldn't he be prebilling?
couldn't we be prebilling?
couldn't you be prebilling?
couldn't they be prebilling? 	couldn't I have prebilled?
couldn't you have prebilled?
couldn't he have prebilled?
couldn't we have prebilled?
couldn't you have prebilled?
couldn't they have prebilled? 	couldn't I have been prebilling?
couldn't you have been prebilling?
couldn't he have been prebilling?
couldn't we have been prebilling?
couldn't you have been prebilling?
couldn't they have been prebilling?