could sextuple
Regular verb: sextuple - sextupled- sextupled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could sextuple
you could sextuple
she could sextuple
we could sextuple
you could sextuple
they could sextuple 	I could be sextupling
you could be sextupling
she could be sextupling
we could be sextupling
you could be sextupling
they could be sextupling	I could have sextupled
you could have sextupled
she could have sextupled
we could have sextupled
you could have sextupled
they could have sextupled	I could have been sextupling
you could have been sextupling
she could have been sextupling
we could have been sextupling
you could have been sextupling
they could have been sextupling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't sextuple
you couldn't sextuple
she couldn't sextuple
we couldn't sextuple
you couldn't sextuple
they couldn't sextuple 	I couldn't be sextupling
you couldn't be sextupling
she couldn't be sextupling
we couldn't be sextupling
you couldn't be sextupling
they couldn't be sextupling	I couldn't have sextupled
you couldn't have sextupled
she couldn't have sextupled
we couldn't have sextupled
you couldn't have sextupled
they couldn't have sextupled	I couldn't have been sextupling
you couldn't have been sextupling
she couldn't have been sextupling
we couldn't have been sextupling
you couldn't have been sextupling
they couldn't have been sextupling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I sextuple?
could you sextuple?
could she sextuple?
could we sextuple?
could you sextuple?
could they sextuple? 	could I be sextupling?
could you be sextupling?
could she be sextupling?
could we be sextupling?
could you be sextupling?
could they be sextupling? 	could I have sextupled?
could you have sextupled?
could she have sextupled?
could we have sextupled?
could you have sextupled?
could they have sextupled? 	could I have been sextupling?
could you have been sextupling?
could she have been sextupling?
could we have been sextupling?
could you have been sextupling?
could they have been sextupling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I sextuple?
couldn't you sextuple?
couldn't she sextuple?
couldn't we sextuple?
couldn't you sextuple?
couldn't they sextuple? 	couldn't I be sextupling?
couldn't you be sextupling?
couldn't she be sextupling?
couldn't we be sextupling?
couldn't you be sextupling?
couldn't they be sextupling? 	couldn't I have sextupled?
couldn't you have sextupled?
couldn't she have sextupled?
couldn't we have sextupled?
couldn't you have sextupled?
couldn't they have sextupled? 	couldn't I have been sextupling?
couldn't you have been sextupling?
couldn't she have been sextupling?
couldn't we have been sextupling?
couldn't you have been sextupling?
couldn't they have been sextupling?