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 cannot yawn
you cannot yawn
she cannot yawn
we cannot yawn
you cannot yawn
they cannot yawn 	I cannot be yawning
you cannot be yawning
she cannot be yawning
we cannot be yawning
you cannot be yawning
they cannot be yawning	I cannot have yawned
you cannot have yawned
she cannot have yawned
we cannot have yawned
you cannot have yawned
they cannot have yawned	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 	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 I not yawn?
can you not yawn?
can she not yawn?
can we not yawn?
can you not yawn?
can they not yawn? 	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? 	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? 	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?