English verb conjugation
CAN YAWN

Regular verb: yawn - yawned - yawned

Affirmation

Simple form	V-ing form
I can yawn you can yawn he can yawn we can yawn you can yawn they can yawn	I can be yawning you can be yawning he can be yawning we can be yawning you can be yawning they can be yawning
Perfect	V-ing perfect
I can have yawned you can have yawned he can have yawned we can have yawned you can have yawned they can have yawned	I can have been yawning you can have been yawning he can have been yawning we can have been yawning you can have been yawning they can have been yawning

Negation

Simple form	V-ing form
I can't yawn you can't yawn he can't yawn we can't yawn you can't yawn they can't yawn	I can't be yawning you can't be yawning he can't be yawning we can't be yawning you can't be yawning they can't be yawning
Perfect	V-ing perfect
I can't have yawned you can't have yawned he can't have yawned we can't have yawned you can't have yawned they can't have yawned	I can't have been yawning you can't have been yawning he can't have been yawning we can't have been yawning you can't have been yawning they can't have been yawning

Interrogative form

Simple form	V-ing form
can I yawn? can you yawn? can he yawn? can we yawn? can you yawn? can they yawn?	can I be yawning? can you be yawning? can he be yawning? can we be yawning? can you be yawning? can they be yawning?
Perfect	V-ing perfect
can I have yawned? can you have yawned? can he have yawned? can we have yawned? can you have yawned? can they have yawned?	can I have been yawning? can you have been yawning? can he have been yawning? can we have been yawning? can you have been yawning? can they have been yawning?

Interro-negative form

Simple form	V-ing form
can't I yawn? can't you yawn? can't he yawn? can't we yawn? can't you yawn? can't they yawn?	can't I be yawning? can't you be yawning? can't he be yawning? can't we be yawning? can't you be yawning? can't they be yawning?
Perfect	V-ing perfect
can't I have yawned? can't you have yawned? can't he have yawned? can't we have yawned? can't you have yawned? can't they have yawned?	can't I have been yawning? can't you have been yawning? can't he have been yawning? can't we have been yawning? can't you have been yawning? can't they have been yawning?