can mark
Regular verb: mark - marked- marked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can mark
you can mark
she can mark
we can mark
you can mark
they can mark 	I can be marking
you can be marking
she can be marking
we can be marking
you can be marking
they can be marking	I can have marked
you can have marked
she can have marked
we can have marked
you can have marked
they can have marked	I can have been marking
you can have been marking
she can have been marking
we can have been marking
you can have been marking
they can have been marking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't mark
you can't mark
she can't mark
we can't mark
you can't mark
they can't mark 	I can't be marking
you can't be marking
she can't be marking
we can't be marking
you can't be marking
they can't be marking	I can't have marked
you can't have marked
she can't have marked
we can't have marked
you can't have marked
they can't have marked	I can't have been marking
you can't have been marking
she can't have been marking
we can't have been marking
you can't have been marking
they can't have been marking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I mark?
can you mark?
can she mark?
can we mark?
can you mark?
can they mark? 	can I be marking?
can you be marking?
can she be marking?
can we be marking?
can you be marking?
can they be marking? 	can I have marked?
can you have marked?
can she have marked?
can we have marked?
can you have marked?
can they have marked? 	can I have been marking?
can you have been marking?
can she have been marking?
can we have been marking?
can you have been marking?
can they have been marking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I mark?
can't you mark?
can't she mark?
can't we mark?
can't you mark?
can't they mark? 	can't I be marking?
can't you be marking?
can't she be marking?
can't we be marking?
can't you be marking?
can't they be marking? 	can't I have marked?
can't you have marked?
can't she have marked?
can't we have marked?
can't you have marked?
can't they have marked? 	can't I have been marking?
can't you have been marking?
can't she have been marking?
can't we have been marking?
can't you have been marking?
can't they have been marking?