should purchase
Regular verb: purchase - purchased- purchased

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd purchase
you'd purchase
he'd purchase
we'd purchase
you'd purchase
they'd purchase 	I'd be purchasing
you'd be purchasing
he'd be purchasing
we'd be purchasing
you'd be purchasing
they'd be purchasing	I should've purchased
you should've purchased
he should've purchased
we should've purchased
you should've purchased
they should've purchased	I should've been purchasing
you should've been purchasing
he should've been purchasing
we should've been purchasing
you should've been purchasing
they should've been purchasing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't purchase
you shouldn't purchase
he shouldn't purchase
we shouldn't purchase
you shouldn't purchase
they shouldn't purchase 	I shouldn't be purchasing
you shouldn't be purchasing
he shouldn't be purchasing
we shouldn't be purchasing
you shouldn't be purchasing
they shouldn't be purchasing	I shouldn't have purchased
you shouldn't have purchased
he shouldn't have purchased
we shouldn't have purchased
you shouldn't have purchased
they shouldn't have purchased	I shouldn't have been purchasing
you shouldn't have been purchasing
he shouldn't have been purchasing
we shouldn't have been purchasing
you shouldn't have been purchasing
they shouldn't have been purchasing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I purchase?
should you purchase?
should he purchase?
should we purchase?
should you purchase?
should they purchase? 	should I be purchasing?
should you be purchasing?
should he be purchasing?
should we be purchasing?
should you be purchasing?
should they be purchasing? 	should I have purchased?
should you have purchased?
should he have purchased?
should we have purchased?
should you have purchased?
should they have purchased? 	should I have been purchasing?
should you have been purchasing?
should he have been purchasing?
should we have been purchasing?
should you have been purchasing?
should they have been purchasing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I purchase?
shouldn't you purchase?
shouldn't he purchase?
shouldn't we purchase?
shouldn't you purchase?
shouldn't they purchase? 	shouldn't I be purchasing?
shouldn't you be purchasing?
shouldn't he be purchasing?
shouldn't we be purchasing?
shouldn't you be purchasing?
shouldn't they be purchasing? 	shouldn't I have purchased?
shouldn't you have purchased?
shouldn't he have purchased?
shouldn't we have purchased?
shouldn't you have purchased?
shouldn't they have purchased? 	shouldn't I have been purchasing?
shouldn't you have been purchasing?
shouldn't he have been purchasing?
shouldn't we have been purchasing?
shouldn't you have been purchasing?
shouldn't they have been purchasing?