English verb conjugation
COULD MYSTIFY

Regular verb: mystify - mystified - mystified

Affirmation

Simple form	V-ing form
I could mystify you could mystify he could mystify we could mystify you could mystify they could mystify	I could be mystifying you could be mystifying he could be mystifying we could be mystifying you could be mystifying they could be mystifying
Perfect	V-ing perfect
I could have mystified you could have mystified he could have mystified we could have mystified you could have mystified they could have mystified	I could have been mystifying you could have been mystifying he could have been mystifying we could have been mystifying you could have been mystifying they could have been mystifying

Negation

Simple form	V-ing form
I couldn't mystify you couldn't mystify he couldn't mystify we couldn't mystify you couldn't mystify they couldn't mystify	I couldn't be mystifying you couldn't be mystifying he couldn't be mystifying we couldn't be mystifying you couldn't be mystifying they couldn't be mystifying
Perfect	V-ing perfect
I couldn't have mystified you couldn't have mystified he couldn't have mystified we couldn't have mystified you couldn't have mystified they couldn't have mystified	I couldn't have been mystifying you couldn't have been mystifying he couldn't have been mystifying we couldn't have been mystifying you couldn't have been mystifying they couldn't have been mystifying

Interrogative form

Simple form	V-ing form
could I mystify? could you mystify? could he mystify? could we mystify? could you mystify? could they mystify?	could I be mystifying? could you be mystifying? could he be mystifying? could we be mystifying? could you be mystifying? could they be mystifying?
Perfect	V-ing perfect
could I have mystified? could you have mystified? could he have mystified? could we have mystified? could you have mystified? could they have mystified?	could I have been mystifying? could you have been mystifying? could he have been mystifying? could we have been mystifying? could you have been mystifying? could they have been mystifying?

Interro-negative form

Simple form	V-ing form
couldn't I mystify? couldn't you mystify? couldn't he mystify? couldn't we mystify? couldn't you mystify? couldn't they mystify?	couldn't I be mystifying? couldn't you be mystifying? couldn't he be mystifying? couldn't we be mystifying? couldn't you be mystifying? couldn't they be mystifying?
Perfect	V-ing perfect
couldn't I have mystified? couldn't you have mystified? couldn't he have mystified? couldn't we have mystified? couldn't you have mystified? couldn't they have mystified?	couldn't I have been mystifying? couldn't you have been mystifying? couldn't he have been mystifying? couldn't we have been mystifying? couldn't you have been mystifying? couldn't they have been mystifying?