I can practice you can practice she can practice we can practice you can practice they can practice
V-ing form
I can be practicing you can be practicing she can be practicing we can be practicing you can be practicing they can be practicing
Perfect
I can have practiced you can have practiced she can have practiced we can have practiced you can have practiced they can have practiced
V-ing perfect
I can have been practicing you can have been practicing she can have been practicing we can have been practicing you can have been practicing they can have been practicing
Negation
Simple form
I cannot practice you cannot practice she cannot practice we cannot practice you cannot practice they cannot practice
V-ing form
I cannot be practicing you cannot be practicing she cannot be practicing we cannot be practicing you cannot be practicing they cannot be practicing
Perfect
I cannot have practiced you cannot have practiced she cannot have practiced we cannot have practiced you cannot have practiced they cannot have practiced
V-ing perfect
I cannot have been practicing you cannot have been practicing she cannot have been practicing we cannot have been practicing you cannot have been practicing they cannot have been practicing
Interrogative form
Simple form
can I practice? can you practice? can she practice? can we practice? can you practice? can they practice?
V-ing form
can I be practicing? can you be practicing? can she be practicing? can we be practicing? can you be practicing? can they be practicing?
Perfect
can I have practiced? can you have practiced? can she have practiced? can we have practiced? can you have practiced? can they have practiced?
V-ing perfect
can I have been practicing? can you have been practicing? can she have been practicing? can we have been practicing? can you have been practicing? can they have been practicing?
Interro-negative form
Simple form
can I not practice? can you not practice? can she not practice? can we not practice? can you not practice? can they not practice?
V-ing form
can I not be practicing? can you not be practicing? can she not be practicing? can we not be practicing? can you not be practicing? can they not be practicing?
Perfect
can I not have practiced? can you not have practiced? can she not have practiced? can we not have practiced? can you not have practiced? can they not have practiced?
V-ing perfect
can I not have been practicing? can you not have been practicing? can she not have been practicing? can we not have been practicing? can you not have been practicing? can they not have been practicing?