could triple
Regular verb: triple - tripled- tripled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could triple
you could triple
she could triple
we could triple
you could triple
they could triple 	I could be tripling
you could be tripling
she could be tripling
we could be tripling
you could be tripling
they could be tripling	I could have tripled
you could have tripled
she could have tripled
we could have tripled
you could have tripled
they could have tripled	I could have been tripling
you could have been tripling
she could have been tripling
we could have been tripling
you could have been tripling
they could have been tripling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't triple
you couldn't triple
she couldn't triple
we couldn't triple
you couldn't triple
they couldn't triple 	I couldn't be tripling
you couldn't be tripling
she couldn't be tripling
we couldn't be tripling
you couldn't be tripling
they couldn't be tripling	I couldn't have tripled
you couldn't have tripled
she couldn't have tripled
we couldn't have tripled
you couldn't have tripled
they couldn't have tripled	I couldn't have been tripling
you couldn't have been tripling
she couldn't have been tripling
we couldn't have been tripling
you couldn't have been tripling
they couldn't have been tripling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I triple?
could you triple?
could she triple?
could we triple?
could you triple?
could they triple? 	could I be tripling?
could you be tripling?
could she be tripling?
could we be tripling?
could you be tripling?
could they be tripling? 	could I have tripled?
could you have tripled?
could she have tripled?
could we have tripled?
could you have tripled?
could they have tripled? 	could I have been tripling?
could you have been tripling?
could she have been tripling?
could we have been tripling?
could you have been tripling?
could they have been tripling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I triple?
couldn't you triple?
couldn't she triple?
couldn't we triple?
couldn't you triple?
couldn't they triple? 	couldn't I be tripling?
couldn't you be tripling?
couldn't she be tripling?
couldn't we be tripling?
couldn't you be tripling?
couldn't they be tripling? 	couldn't I have tripled?
couldn't you have tripled?
couldn't she have tripled?
couldn't we have tripled?
couldn't you have tripled?
couldn't they have tripled? 	couldn't I have been tripling?
couldn't you have been tripling?
couldn't she have been tripling?
couldn't we have been tripling?
couldn't you have been tripling?
couldn't they have been tripling?