English verb conjugation
CAN MARK

Regular verb: mark - marked - marked

Affirmation

Simple form	V-ing form
I can mark you can mark he can mark we can mark you can mark they can mark	I can be marking you can be marking he can be marking we can be marking you can be marking they can be marking
Perfect	V-ing perfect
I can have marked you can have marked he 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 he 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
I cannot mark you cannot mark he cannot mark we cannot mark you cannot mark they cannot mark	I cannot be marking you cannot be marking he cannot be marking we cannot be marking you cannot be marking they cannot be marking
Perfect	V-ing perfect
I cannot have marked you cannot have marked he cannot have marked we cannot have marked you cannot have marked they cannot have marked	I cannot have been marking you cannot have been marking he cannot have been marking we cannot have been marking you cannot have been marking they cannot have been marking

Interrogative form

Simple form	V-ing form
can I mark? can you mark? can he mark? can we mark? can you mark? can they mark?	can I be marking? can you be marking? can he be marking? can we be marking? can you be marking? can they be marking?
Perfect	V-ing perfect
can I have marked? can you have marked? can he 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 he 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
can I not mark? can you not mark? can he not mark? can we not mark? can you not mark? can they not mark?	can I not be marking? can you not be marking? can he not be marking? can we not be marking? can you not be marking? can they not be marking?
Perfect	V-ing perfect
can I not have marked? can you not have marked? can he not have marked? can we not have marked? can you not have marked? can they not have marked?	can I not have been marking? can you not have been marking? can he not have been marking? can we not have been marking? can you not have been marking? can they not have been marking?