can master
Regular verb: master - mastered- mastered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can master
you can master
she can master
we can master
you can master
they can master 	I can be mastering
you can be mastering
she can be mastering
we can be mastering
you can be mastering
they can be mastering	I can have mastered
you can have mastered
she can have mastered
we can have mastered
you can have mastered
they can have mastered	I can have been mastering
you can have been mastering
she can have been mastering
we can have been mastering
you can have been mastering
they can have been mastering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot master
you cannot master
she cannot master
we cannot master
you cannot master
they cannot master 	I cannot be mastering
you cannot be mastering
she cannot be mastering
we cannot be mastering
you cannot be mastering
they cannot be mastering	I cannot have mastered
you cannot have mastered
she cannot have mastered
we cannot have mastered
you cannot have mastered
they cannot have mastered	I cannot have been mastering
you cannot have been mastering
she cannot have been mastering
we cannot have been mastering
you cannot have been mastering
they cannot have been mastering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I master?
can you master?
can she master?
can we master?
can you master?
can they master? 	can I be mastering?
can you be mastering?
can she be mastering?
can we be mastering?
can you be mastering?
can they be mastering? 	can I have mastered?
can you have mastered?
can she have mastered?
can we have mastered?
can you have mastered?
can they have mastered? 	can I have been mastering?
can you have been mastering?
can she have been mastering?
can we have been mastering?
can you have been mastering?
can they have been mastering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not master?
can you not master?
can she not master?
can we not master?
can you not master?
can they not master? 	can I not be mastering?
can you not be mastering?
can she not be mastering?
can we not be mastering?
can you not be mastering?
can they not be mastering? 	can I not have mastered?
can you not have mastered?
can she not have mastered?
can we not have mastered?
can you not have mastered?
can they not have mastered? 	can I not have been mastering?
can you not have been mastering?
can she not have been mastering?
can we not have been mastering?
can you not have been mastering?
can they not have been mastering?