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 can't mark you can't mark he 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 he can't be marking we can't be marking you can't be marking they can't be marking
Perfect	V-ing perfect
I can't have marked you can't have marked he 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 he 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
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't I mark? can't you mark? can't he 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 he be marking? can't we be marking? can't you be marking? can't they be marking?
Perfect	V-ing perfect
can't I have marked? can't you have marked? can't he 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 he have been marking? can't we have been marking? can't you have been marking? can't they have been marking?