could skulk
Verbo regular: skulk - skulked- skulked

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could skulk
you could skulk
he could skulk
we could skulk
you could skulk
they could skulk 	I could be skulking
you could be skulking
he could be skulking
we could be skulking
you could be skulking
they could be skulking	I could have skulked
you could have skulked
he could have skulked
we could have skulked
you could have skulked
they could have skulked	I could have been skulking
you could have been skulking
he could have been skulking
we could have been skulking
you could have been skulking
they could have been skulking	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't skulk
you couldn't skulk
he couldn't skulk
we couldn't skulk
you couldn't skulk
they couldn't skulk 	I couldn't be skulking
you couldn't be skulking
he couldn't be skulking
we couldn't be skulking
you couldn't be skulking
they couldn't be skulking	I couldn't have skulked
you couldn't have skulked
he couldn't have skulked
we couldn't have skulked
you couldn't have skulked
they couldn't have skulked	I couldn't have been skulking
you couldn't have been skulking
he couldn't have been skulking
we couldn't have been skulking
you couldn't have been skulking
they couldn't have been skulking	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I skulk?
could you skulk?
could he skulk?
could we skulk?
could you skulk?
could they skulk? 	could I be skulking?
could you be skulking?
could he be skulking?
could we be skulking?
could you be skulking?
could they be skulking? 	could I have skulked?
could you have skulked?
could he have skulked?
could we have skulked?
could you have skulked?
could they have skulked? 	could I have been skulking?
could you have been skulking?
could he have been skulking?
could we have been skulking?
could you have been skulking?
could they have been skulking? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I skulk?
couldn't you skulk?
couldn't he skulk?
couldn't we skulk?
couldn't you skulk?
couldn't they skulk? 	couldn't I be skulking?
couldn't you be skulking?
couldn't he be skulking?
couldn't we be skulking?
couldn't you be skulking?
couldn't they be skulking? 	couldn't I have skulked?
couldn't you have skulked?
couldn't he have skulked?
couldn't we have skulked?
couldn't you have skulked?
couldn't they have skulked? 	couldn't I have been skulking?
couldn't you have been skulking?
couldn't he have been skulking?
couldn't we have been skulking?
couldn't you have been skulking?
couldn't they have been skulking?