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 can't lock you can't lock he can't lock we can't lock you can't lock they can't lock
V-ing form
I can't be locking you can't be locking he can't be locking we can't be locking you can't be locking they can't be locking
Perfect
I can't have locked you can't have locked he can't have locked we can't have locked you can't have locked they can't have locked
V-ing perfect
I can't have been locking you can't have been locking he can't have been locking we can't have been locking you can't have been locking they can't 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't I lock? can't you lock? can't he lock? can't we lock? can't you lock? can't they lock?
V-ing form
can't I be locking? can't you be locking? can't he be locking? can't we be locking? can't you be locking? can't they be locking?
Perfect
can't I have locked? can't you have locked? can't he have locked? can't we have locked? can't you have locked? can't they have locked?
V-ing perfect
can't I have been locking? can't you have been locking? can't he have been locking? can't we have been locking? can't you have been locking? can't they have been locking?