could undulate
Verbo regular: undulate - undulated- undulated

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could undulate
you could undulate
he could undulate
we could undulate
you could undulate
they could undulate 	I could be undulating
you could be undulating
he could be undulating
we could be undulating
you could be undulating
they could be undulating	I could have undulated
you could have undulated
he could have undulated
we could have undulated
you could have undulated
they could have undulated	I could have been undulating
you could have been undulating
he could have been undulating
we could have been undulating
you could have been undulating
they could have been undulating	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't undulate
you couldn't undulate
he couldn't undulate
we couldn't undulate
you couldn't undulate
they couldn't undulate 	I couldn't be undulating
you couldn't be undulating
he couldn't be undulating
we couldn't be undulating
you couldn't be undulating
they couldn't be undulating	I couldn't have undulated
you couldn't have undulated
he couldn't have undulated
we couldn't have undulated
you couldn't have undulated
they couldn't have undulated	I couldn't have been undulating
you couldn't have been undulating
he couldn't have been undulating
we couldn't have been undulating
you couldn't have been undulating
they couldn't have been undulating	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I undulate?
could you undulate?
could he undulate?
could we undulate?
could you undulate?
could they undulate? 	could I be undulating?
could you be undulating?
could he be undulating?
could we be undulating?
could you be undulating?
could they be undulating? 	could I have undulated?
could you have undulated?
could he have undulated?
could we have undulated?
could you have undulated?
could they have undulated? 	could I have been undulating?
could you have been undulating?
could he have been undulating?
could we have been undulating?
could you have been undulating?
could they have been undulating? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I undulate?
couldn't you undulate?
couldn't he undulate?
couldn't we undulate?
couldn't you undulate?
couldn't they undulate? 	couldn't I be undulating?
couldn't you be undulating?
couldn't he be undulating?
couldn't we be undulating?
couldn't you be undulating?
couldn't they be undulating? 	couldn't I have undulated?
couldn't you have undulated?
couldn't he have undulated?
couldn't we have undulated?
couldn't you have undulated?
couldn't they have undulated? 	couldn't I have been undulating?
couldn't you have been undulating?
couldn't he have been undulating?
couldn't we have been undulating?
couldn't you have been undulating?
couldn't they have been undulating?