can tiff
Regular verb: tiff - tiffed- tiffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can tiff
you can tiff
he can tiff
we can tiff
you can tiff
they can tiff 	I can be tiffing
you can be tiffing
he can be tiffing
we can be tiffing
you can be tiffing
they can be tiffing	I can have tiffed
you can have tiffed
he can have tiffed
we can have tiffed
you can have tiffed
they can have tiffed	I can have been tiffing
you can have been tiffing
he can have been tiffing
we can have been tiffing
you can have been tiffing
they can have been tiffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't tiff
you can't tiff
he can't tiff
we can't tiff
you can't tiff
they can't tiff 	I can't be tiffing
you can't be tiffing
he can't be tiffing
we can't be tiffing
you can't be tiffing
they can't be tiffing	I can't have tiffed
you can't have tiffed
he can't have tiffed
we can't have tiffed
you can't have tiffed
they can't have tiffed	I can't have been tiffing
you can't have been tiffing
he can't have been tiffing
we can't have been tiffing
you can't have been tiffing
they can't have been tiffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I tiff?
can you tiff?
can he tiff?
can we tiff?
can you tiff?
can they tiff? 	can I be tiffing?
can you be tiffing?
can he be tiffing?
can we be tiffing?
can you be tiffing?
can they be tiffing? 	can I have tiffed?
can you have tiffed?
can he have tiffed?
can we have tiffed?
can you have tiffed?
can they have tiffed? 	can I have been tiffing?
can you have been tiffing?
can he have been tiffing?
can we have been tiffing?
can you have been tiffing?
can they have been tiffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I tiff?
can't you tiff?
can't he tiff?
can't we tiff?
can't you tiff?
can't they tiff? 	can't I be tiffing?
can't you be tiffing?
can't he be tiffing?
can't we be tiffing?
can't you be tiffing?
can't they be tiffing? 	can't I have tiffed?
can't you have tiffed?
can't he have tiffed?
can't we have tiffed?
can't you have tiffed?
can't they have tiffed? 	can't I have been tiffing?
can't you have been tiffing?
can't he have been tiffing?
can't we have been tiffing?
can't you have been tiffing?
can't they have been tiffing?