English verb conjugation
CAN TURN

Regular verb: turn - turned - turned

Affirmation

Simple form	V-ing form
I can turn you can turn he can turn we can turn you can turn they can turn	I can be turning you can be turning he can be turning we can be turning you can be turning they can be turning
Perfect	V-ing perfect
I can have turned you can have turned he can have turned we can have turned you can have turned they can have turned	I can have been turning you can have been turning he can have been turning we can have been turning you can have been turning they can have been turning

Negation

Simple form	V-ing form
I cannot turn you cannot turn he cannot turn we cannot turn you cannot turn they cannot turn	I cannot be turning you cannot be turning he cannot be turning we cannot be turning you cannot be turning they cannot be turning
Perfect	V-ing perfect
I cannot have turned you cannot have turned he cannot have turned we cannot have turned you cannot have turned they cannot have turned	I cannot have been turning you cannot have been turning he cannot have been turning we cannot have been turning you cannot have been turning they cannot have been turning

Interrogative form

Simple form	V-ing form
can I turn? can you turn? can he turn? can we turn? can you turn? can they turn?	can I be turning? can you be turning? can he be turning? can we be turning? can you be turning? can they be turning?
Perfect	V-ing perfect
can I have turned? can you have turned? can he have turned? can we have turned? can you have turned? can they have turned?	can I have been turning? can you have been turning? can he have been turning? can we have been turning? can you have been turning? can they have been turning?

Interro-negative form

Simple form	V-ing form
can I not turn? can you not turn? can he not turn? can we not turn? can you not turn? can they not turn?	can I not be turning? can you not be turning? can he not be turning? can we not be turning? can you not be turning? can they not be turning?
Perfect	V-ing perfect
can I not have turned? can you not have turned? can he not have turned? can we not have turned? can you not have turned? can they not have turned?	can I not have been turning? can you not have been turning? can he not have been turning? can we not have been turning? can you not have been turning? can they not have been turning?