can yawn
Regular verb: yawn - yawned- yawned

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