I can lock you can lock he can lock we can lock you can lock they can lock
V-ing form
I can be locking you can be locking he can be locking we can be locking you can be locking they can be locking
Perfect
I can have locked you can have locked he can have locked we can have locked you can have locked they can have locked
V-ing perfect
I can have been locking you can have been locking he can have been locking we can have been locking you can have been locking they can have been locking
Negation
Simple form
I cannot lock you cannot lock he cannot lock we cannot lock you cannot lock they cannot lock
V-ing form
I cannot be locking you cannot be locking he cannot be locking we cannot be locking you cannot be locking they cannot be locking
Perfect
I cannot have locked you cannot have locked he cannot have locked we cannot have locked you cannot have locked they cannot have locked
V-ing perfect
I cannot have been locking you cannot have been locking he cannot have been locking we cannot have been locking you cannot have been locking they cannot have been locking
Interrogative form
Simple form
can I lock? can you lock? can he lock? can we lock? can you lock? can they lock?
V-ing form
can I be locking? can you be locking? can he be locking? can we be locking? can you be locking? can they be locking?
Perfect
can I have locked? can you have locked? can he have locked? can we have locked? can you have locked? can they have locked?
V-ing perfect
can I have been locking? can you have been locking? can he have been locking? can we have been locking? can you have been locking? can they have been locking?
Interro-negative form
Simple form
can I not lock? can you not lock? can he not lock? can we not lock? can you not lock? can they not lock?
V-ing form
can I not be locking? can you not be locking? can he not be locking? can we not be locking? can you not be locking? can they not be locking?
Perfect
can I not have locked? can you not have locked? can he not have locked? can we not have locked? can you not have locked? can they not have locked?
V-ing perfect
can I not have been locking? can you not have been locking? can he not have been locking? can we not have been locking? can you not have been locking? can they not have been locking?