I can yawn you can yawn she can yawn we can yawn you can yawn they can yawn
V-ing form
I can be yawning you can be yawning she can be yawning we can be yawning you can be yawning they can be yawning
Perfect
I can have yawned you can have yawned she can have yawned we can have yawned you can have yawned they can have yawned
V-ing perfect
I can have been yawning you can have been yawning she can have been yawning we can have been yawning you can have been yawning they can have been yawning
Negation
Simple form
I cannot yawn you cannot yawn she cannot yawn we cannot yawn you cannot yawn they cannot yawn
V-ing form
I cannot be yawning you cannot be yawning she cannot be yawning we cannot be yawning you cannot be yawning they cannot be yawning
Perfect
I cannot have yawned you cannot have yawned she cannot have yawned we cannot have yawned you cannot have yawned they cannot have yawned
V-ing perfect
I cannot have been yawning you cannot have been yawning she cannot have been yawning we cannot have been yawning you cannot have been yawning they cannot have been yawning
Interrogative form
Simple form
can I yawn? can you yawn? can she yawn? can we yawn? can you yawn? can they yawn?
V-ing form
can I be yawning? can you be yawning? can she be yawning? can we be yawning? can you be yawning? can they be yawning?
Perfect
can I have yawned? can you have yawned? can she have yawned? can we have yawned? can you have yawned? can they have yawned?
V-ing perfect
can I have been yawning? can you have been yawning? can she have been yawning? can we have been yawning? can you have been yawning? can they have been yawning?
Interro-negative form
Simple form
can I not yawn? can you not yawn? can she not yawn? can we not yawn? can you not yawn? can they not yawn?
V-ing form
can I not be yawning? can you not be yawning? can she not be yawning? can we not be yawning? can you not be yawning? can they not be yawning?
Perfect
can I not have yawned? can you not have yawned? can she not have yawned? can we not have yawned? can you not have yawned? can they not have yawned?
V-ing perfect
can I not have been yawning? can you not have been yawning? can she not have been yawning? can we not have been yawning? can you not have been yawning? can they not have been yawning?