could shark
Regular verb: shark - sharked- sharked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could shark
you could shark
he could shark
we could shark
you could shark
they could shark 	I could be sharking
you could be sharking
he could be sharking
we could be sharking
you could be sharking
they could be sharking	I could have sharked
you could have sharked
he could have sharked
we could have sharked
you could have sharked
they could have sharked	I could have been sharking
you could have been sharking
he could have been sharking
we could have been sharking
you could have been sharking
they could have been sharking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't shark
you couldn't shark
he couldn't shark
we couldn't shark
you couldn't shark
they couldn't shark 	I couldn't be sharking
you couldn't be sharking
he couldn't be sharking
we couldn't be sharking
you couldn't be sharking
they couldn't be sharking	I couldn't have sharked
you couldn't have sharked
he couldn't have sharked
we couldn't have sharked
you couldn't have sharked
they couldn't have sharked	I couldn't have been sharking
you couldn't have been sharking
he couldn't have been sharking
we couldn't have been sharking
you couldn't have been sharking
they couldn't have been sharking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I shark?
could you shark?
could he shark?
could we shark?
could you shark?
could they shark? 	could I be sharking?
could you be sharking?
could he be sharking?
could we be sharking?
could you be sharking?
could they be sharking? 	could I have sharked?
could you have sharked?
could he have sharked?
could we have sharked?
could you have sharked?
could they have sharked? 	could I have been sharking?
could you have been sharking?
could he have been sharking?
could we have been sharking?
could you have been sharking?
could they have been sharking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I shark?
couldn't you shark?
couldn't he shark?
couldn't we shark?
couldn't you shark?
couldn't they shark? 	couldn't I be sharking?
couldn't you be sharking?
couldn't he be sharking?
couldn't we be sharking?
couldn't you be sharking?
couldn't they be sharking? 	couldn't I have sharked?
couldn't you have sharked?
couldn't he have sharked?
couldn't we have sharked?
couldn't you have sharked?
couldn't they have sharked? 	couldn't I have been sharking?
couldn't you have been sharking?
couldn't he have been sharking?
couldn't we have been sharking?
couldn't you have been sharking?
couldn't they have been sharking?