English verb conjugation
CAN MASTER

Regular verb: master - mastered - mastered

Affirmation

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