I can exchange you can exchange he can exchange we can exchange you can exchange they can exchange
V-ing form
I can be exchanging you can be exchanging he can be exchanging we can be exchanging you can be exchanging they can be exchanging
Perfect
I can have exchanged you can have exchanged he can have exchanged we can have exchanged you can have exchanged they can have exchanged
V-ing perfect
I can have been exchanging you can have been exchanging he can have been exchanging we can have been exchanging you can have been exchanging they can have been exchanging
Negation
Simple form
I cannot exchange you cannot exchange he cannot exchange we cannot exchange you cannot exchange they cannot exchange
V-ing form
I cannot be exchanging you cannot be exchanging he cannot be exchanging we cannot be exchanging you cannot be exchanging they cannot be exchanging
Perfect
I cannot have exchanged you cannot have exchanged he cannot have exchanged we cannot have exchanged you cannot have exchanged they cannot have exchanged
V-ing perfect
I cannot have been exchanging you cannot have been exchanging he cannot have been exchanging we cannot have been exchanging you cannot have been exchanging they cannot have been exchanging
Interrogative form
Simple form
can I exchange? can you exchange? can he exchange? can we exchange? can you exchange? can they exchange?
V-ing form
can I be exchanging? can you be exchanging? can he be exchanging? can we be exchanging? can you be exchanging? can they be exchanging?
Perfect
can I have exchanged? can you have exchanged? can he have exchanged? can we have exchanged? can you have exchanged? can they have exchanged?
V-ing perfect
can I have been exchanging? can you have been exchanging? can he have been exchanging? can we have been exchanging? can you have been exchanging? can they have been exchanging?
Interro-negative form
Simple form
can I not exchange? can you not exchange? can he not exchange? can we not exchange? can you not exchange? can they not exchange?
V-ing form
can I not be exchanging? can you not be exchanging? can he not be exchanging? can we not be exchanging? can you not be exchanging? can they not be exchanging?
Perfect
can I not have exchanged? can you not have exchanged? can he not have exchanged? can we not have exchanged? can you not have exchanged? can they not have exchanged?
V-ing perfect
can I not have been exchanging? can you not have been exchanging? can he not have been exchanging? can we not have been exchanging? can you not have been exchanging? can they not have been exchanging?