should crumble
Regular verb: crumble - crumbled- crumbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd crumble
you'd crumble
he'd crumble
we'd crumble
you'd crumble
they'd crumble 	I'd be crumbling
you'd be crumbling
he'd be crumbling
we'd be crumbling
you'd be crumbling
they'd be crumbling	I should've crumbled
you should've crumbled
he should've crumbled
we should've crumbled
you should've crumbled
they should've crumbled	I should've been crumbling
you should've been crumbling
he should've been crumbling
we should've been crumbling
you should've been crumbling
they should've been crumbling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't crumble
you shouldn't crumble
he shouldn't crumble
we shouldn't crumble
you shouldn't crumble
they shouldn't crumble 	I shouldn't be crumbling
you shouldn't be crumbling
he shouldn't be crumbling
we shouldn't be crumbling
you shouldn't be crumbling
they shouldn't be crumbling	I shouldn't have crumbled
you shouldn't have crumbled
he shouldn't have crumbled
we shouldn't have crumbled
you shouldn't have crumbled
they shouldn't have crumbled	I shouldn't have been crumbling
you shouldn't have been crumbling
he shouldn't have been crumbling
we shouldn't have been crumbling
you shouldn't have been crumbling
they shouldn't have been crumbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I crumble?
should you crumble?
should he crumble?
should we crumble?
should you crumble?
should they crumble? 	should I be crumbling?
should you be crumbling?
should he be crumbling?
should we be crumbling?
should you be crumbling?
should they be crumbling? 	should I have crumbled?
should you have crumbled?
should he have crumbled?
should we have crumbled?
should you have crumbled?
should they have crumbled? 	should I have been crumbling?
should you have been crumbling?
should he have been crumbling?
should we have been crumbling?
should you have been crumbling?
should they have been crumbling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I crumble?
shouldn't you crumble?
shouldn't he crumble?
shouldn't we crumble?
shouldn't you crumble?
shouldn't they crumble? 	shouldn't I be crumbling?
shouldn't you be crumbling?
shouldn't he be crumbling?
shouldn't we be crumbling?
shouldn't you be crumbling?
shouldn't they be crumbling? 	shouldn't I have crumbled?
shouldn't you have crumbled?
shouldn't he have crumbled?
shouldn't we have crumbled?
shouldn't you have crumbled?
shouldn't they have crumbled? 	shouldn't I have been crumbling?
shouldn't you have been crumbling?
shouldn't he have been crumbling?
shouldn't we have been crumbling?
shouldn't you have been crumbling?
shouldn't they have been crumbling?