I can mark you can mark he can mark we can mark you can mark they can mark
V-ing form
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
I can have marked you can have marked he can have marked we can have marked you can have marked they can have marked
V-ing perfect
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
I cannot mark you cannot mark he cannot mark we cannot mark you cannot mark they cannot mark
V-ing form
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
I cannot have marked you cannot have marked he cannot have marked we cannot have marked you cannot have marked they cannot have marked
V-ing perfect
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
can I mark? can you mark? can he mark? can we mark? can you mark? can they mark?
V-ing form
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
can I have marked? can you have marked? can he have marked? can we have marked? can you have marked? can they have marked?
V-ing perfect
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
can I not mark? can you not mark? can he not mark? can we not mark? can you not mark? can they not mark?
V-ing form
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
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?
V-ing perfect
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?