could cavern
Regular verb: cavern - caverned- caverned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could cavern
you could cavern
she could cavern
we could cavern
you could cavern
they could cavern 	I could be caverning
you could be caverning
she could be caverning
we could be caverning
you could be caverning
they could be caverning	I could have caverned
you could have caverned
she could have caverned
we could have caverned
you could have caverned
they could have caverned	I could have been caverning
you could have been caverning
she could have been caverning
we could have been caverning
you could have been caverning
they could have been caverning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't cavern
you couldn't cavern
she couldn't cavern
we couldn't cavern
you couldn't cavern
they couldn't cavern 	I couldn't be caverning
you couldn't be caverning
she couldn't be caverning
we couldn't be caverning
you couldn't be caverning
they couldn't be caverning	I couldn't have caverned
you couldn't have caverned
she couldn't have caverned
we couldn't have caverned
you couldn't have caverned
they couldn't have caverned	I couldn't have been caverning
you couldn't have been caverning
she couldn't have been caverning
we couldn't have been caverning
you couldn't have been caverning
they couldn't have been caverning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I cavern?
could you cavern?
could she cavern?
could we cavern?
could you cavern?
could they cavern? 	could I be caverning?
could you be caverning?
could she be caverning?
could we be caverning?
could you be caverning?
could they be caverning? 	could I have caverned?
could you have caverned?
could she have caverned?
could we have caverned?
could you have caverned?
could they have caverned? 	could I have been caverning?
could you have been caverning?
could she have been caverning?
could we have been caverning?
could you have been caverning?
could they have been caverning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I cavern?
couldn't you cavern?
couldn't she cavern?
couldn't we cavern?
couldn't you cavern?
couldn't they cavern? 	couldn't I be caverning?
couldn't you be caverning?
couldn't she be caverning?
couldn't we be caverning?
couldn't you be caverning?
couldn't they be caverning? 	couldn't I have caverned?
couldn't you have caverned?
couldn't she have caverned?
couldn't we have caverned?
couldn't you have caverned?
couldn't they have caverned? 	couldn't I have been caverning?
couldn't you have been caverning?
couldn't she have been caverning?
couldn't we have been caverning?
couldn't you have been caverning?
couldn't they have been caverning?