I can commence you can commence he can commence we can commence you can commence they can commence
V-ing form
I can be commencing you can be commencing he can be commencing we can be commencing you can be commencing they can be commencing
Perfect
I can have commenced you can have commenced he can have commenced we can have commenced you can have commenced they can have commenced
V-ing perfect
I can have been commencing you can have been commencing he can have been commencing we can have been commencing you can have been commencing they can have been commencing
Negation
Simple form
I cannot commence you cannot commence he cannot commence we cannot commence you cannot commence they cannot commence
V-ing form
I cannot be commencing you cannot be commencing he cannot be commencing we cannot be commencing you cannot be commencing they cannot be commencing
Perfect
I cannot have commenced you cannot have commenced he cannot have commenced we cannot have commenced you cannot have commenced they cannot have commenced
V-ing perfect
I cannot have been commencing you cannot have been commencing he cannot have been commencing we cannot have been commencing you cannot have been commencing they cannot have been commencing
Interrogative form
Simple form
can I commence? can you commence? can he commence? can we commence? can you commence? can they commence?
V-ing form
can I be commencing? can you be commencing? can he be commencing? can we be commencing? can you be commencing? can they be commencing?
Perfect
can I have commenced? can you have commenced? can he have commenced? can we have commenced? can you have commenced? can they have commenced?
V-ing perfect
can I have been commencing? can you have been commencing? can he have been commencing? can we have been commencing? can you have been commencing? can they have been commencing?
Interro-negative form
Simple form
can I not commence? can you not commence? can he not commence? can we not commence? can you not commence? can they not commence?
V-ing form
can I not be commencing? can you not be commencing? can he not be commencing? can we not be commencing? can you not be commencing? can they not be commencing?
Perfect
can I not have commenced? can you not have commenced? can he not have commenced? can we not have commenced? can you not have commenced? can they not have commenced?
V-ing perfect
can I not have been commencing? can you not have been commencing? can he not have been commencing? can we not have been commencing? can you not have been commencing? can they not have been commencing?