can tower
Regular verb: tower - towered- towered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can tower
you can tower
he can tower
we can tower
you can tower
they can tower 	I can be towering
you can be towering
he can be towering
we can be towering
you can be towering
they can be towering	I can have towered
you can have towered
he can have towered
we can have towered
you can have towered
they can have towered	I can have been towering
you can have been towering
he can have been towering
we can have been towering
you can have been towering
they can have been towering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't tower
you can't tower
he can't tower
we can't tower
you can't tower
they can't tower 	I can't be towering
you can't be towering
he can't be towering
we can't be towering
you can't be towering
they can't be towering	I can't have towered
you can't have towered
he can't have towered
we can't have towered
you can't have towered
they can't have towered	I can't have been towering
you can't have been towering
he can't have been towering
we can't have been towering
you can't have been towering
they can't have been towering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I tower?
can you tower?
can he tower?
can we tower?
can you tower?
can they tower? 	can I be towering?
can you be towering?
can he be towering?
can we be towering?
can you be towering?
can they be towering? 	can I have towered?
can you have towered?
can he have towered?
can we have towered?
can you have towered?
can they have towered? 	can I have been towering?
can you have been towering?
can he have been towering?
can we have been towering?
can you have been towering?
can they have been towering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I tower?
can't you tower?
can't he tower?
can't we tower?
can't you tower?
can't they tower? 	can't I be towering?
can't you be towering?
can't he be towering?
can't we be towering?
can't you be towering?
can't they be towering? 	can't I have towered?
can't you have towered?
can't he have towered?
can't we have towered?
can't you have towered?
can't they have towered? 	can't I have been towering?
can't you have been towering?
can't he have been towering?
can't we have been towering?
can't you have been towering?
can't they have been towering?