can tier
Regular verb: tier - tiered- tiered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can tier
you can tier
he can tier
we can tier
you can tier
they can tier 	I can be tiering
you can be tiering
he can be tiering
we can be tiering
you can be tiering
they can be tiering	I can have tiered
you can have tiered
he can have tiered
we can have tiered
you can have tiered
they can have tiered	I can have been tiering
you can have been tiering
he can have been tiering
we can have been tiering
you can have been tiering
they can have been tiering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't tier
you can't tier
he can't tier
we can't tier
you can't tier
they can't tier 	I can't be tiering
you can't be tiering
he can't be tiering
we can't be tiering
you can't be tiering
they can't be tiering	I can't have tiered
you can't have tiered
he can't have tiered
we can't have tiered
you can't have tiered
they can't have tiered	I can't have been tiering
you can't have been tiering
he can't have been tiering
we can't have been tiering
you can't have been tiering
they can't have been tiering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I tier?
can you tier?
can he tier?
can we tier?
can you tier?
can they tier? 	can I be tiering?
can you be tiering?
can he be tiering?
can we be tiering?
can you be tiering?
can they be tiering? 	can I have tiered?
can you have tiered?
can he have tiered?
can we have tiered?
can you have tiered?
can they have tiered? 	can I have been tiering?
can you have been tiering?
can he have been tiering?
can we have been tiering?
can you have been tiering?
can they have been tiering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I tier?
can't you tier?
can't he tier?
can't we tier?
can't you tier?
can't they tier? 	can't I be tiering?
can't you be tiering?
can't he be tiering?
can't we be tiering?
can't you be tiering?
can't they be tiering? 	can't I have tiered?
can't you have tiered?
can't he have tiered?
can't we have tiered?
can't you have tiered?
can't they have tiered? 	can't I have been tiering?
can't you have been tiering?
can't he have been tiering?
can't we have been tiering?
can't you have been tiering?
can't they have been tiering?