could spark
Regular verb: spark - sparked- sparked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could spark
you could spark
he could spark
we could spark
you could spark
they could spark 	I could be sparking
you could be sparking
he could be sparking
we could be sparking
you could be sparking
they could be sparking	I could have sparked
you could have sparked
he could have sparked
we could have sparked
you could have sparked
they could have sparked	I could have been sparking
you could have been sparking
he could have been sparking
we could have been sparking
you could have been sparking
they could have been sparking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't spark
you couldn't spark
he couldn't spark
we couldn't spark
you couldn't spark
they couldn't spark 	I couldn't be sparking
you couldn't be sparking
he couldn't be sparking
we couldn't be sparking
you couldn't be sparking
they couldn't be sparking	I couldn't have sparked
you couldn't have sparked
he couldn't have sparked
we couldn't have sparked
you couldn't have sparked
they couldn't have sparked	I couldn't have been sparking
you couldn't have been sparking
he couldn't have been sparking
we couldn't have been sparking
you couldn't have been sparking
they couldn't have been sparking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I spark?
could you spark?
could he spark?
could we spark?
could you spark?
could they spark? 	could I be sparking?
could you be sparking?
could he be sparking?
could we be sparking?
could you be sparking?
could they be sparking? 	could I have sparked?
could you have sparked?
could he have sparked?
could we have sparked?
could you have sparked?
could they have sparked? 	could I have been sparking?
could you have been sparking?
could he have been sparking?
could we have been sparking?
could you have been sparking?
could they have been sparking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I spark?
couldn't you spark?
couldn't he spark?
couldn't we spark?
couldn't you spark?
couldn't they spark? 	couldn't I be sparking?
couldn't you be sparking?
couldn't he be sparking?
couldn't we be sparking?
couldn't you be sparking?
couldn't they be sparking? 	couldn't I have sparked?
couldn't you have sparked?
couldn't he have sparked?
couldn't we have sparked?
couldn't you have sparked?
couldn't they have sparked? 	couldn't I have been sparking?
couldn't you have been sparking?
couldn't he have been sparking?
couldn't we have been sparking?
couldn't you have been sparking?
couldn't they have been sparking?