I can mark you can mark she can mark we can mark you can mark they can mark
V-ing form
I can be marking you can be marking she can be marking we can be marking you can be marking they can be marking
Perfect
I can have marked you can have marked she 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 she 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 she cannot mark we cannot mark you cannot mark they cannot mark
V-ing form
I cannot be marking you cannot be marking she cannot be marking we cannot be marking you cannot be marking they cannot be marking
Perfect
I cannot have marked you cannot have marked she 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 she 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 she mark? can we mark? can you mark? can they mark?
V-ing form
can I be marking? can you be marking? can she be marking? can we be marking? can you be marking? can they be marking?
Perfect
can I have marked? can you have marked? can she 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 she 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 she 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 she 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 she 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 she not have been marking? can we not have been marking? can you not have been marking? can they not have been marking?