can undulate
Regular verb: undulate - undulated- undulated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can undulate
you can undulate
he can undulate
we can undulate
you can undulate
they can undulate 	I can be undulating
you can be undulating
he can be undulating
we can be undulating
you can be undulating
they can be undulating	I can have undulated
you can have undulated
he can have undulated
we can have undulated
you can have undulated
they can have undulated	I can have been undulating
you can have been undulating
he can have been undulating
we can have been undulating
you can have been undulating
they can have been undulating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't undulate
you can't undulate
he can't undulate
we can't undulate
you can't undulate
they can't undulate 	I can't be undulating
you can't be undulating
he can't be undulating
we can't be undulating
you can't be undulating
they can't be undulating	I can't have undulated
you can't have undulated
he can't have undulated
we can't have undulated
you can't have undulated
they can't have undulated	I can't have been undulating
you can't have been undulating
he can't have been undulating
we can't have been undulating
you can't have been undulating
they can't have been undulating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I undulate?
can you undulate?
can he undulate?
can we undulate?
can you undulate?
can they undulate? 	can I be undulating?
can you be undulating?
can he be undulating?
can we be undulating?
can you be undulating?
can they be undulating? 	can I have undulated?
can you have undulated?
can he have undulated?
can we have undulated?
can you have undulated?
can they have undulated? 	can I have been undulating?
can you have been undulating?
can he have been undulating?
can we have been undulating?
can you have been undulating?
can they have been undulating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I undulate?
can't you undulate?
can't he undulate?
can't we undulate?
can't you undulate?
can't they undulate? 	can't I be undulating?
can't you be undulating?
can't he be undulating?
can't we be undulating?
can't you be undulating?
can't they be undulating? 	can't I have undulated?
can't you have undulated?
can't he have undulated?
can't we have undulated?
can't you have undulated?
can't they have undulated? 	can't I have been undulating?
can't you have been undulating?
can't he have been undulating?
can't we have been undulating?
can't you have been undulating?
can't they have been undulating?