English verb conjugation
COULD MYSTIFY

Regular verb: mystify - mystified - mystified

Affirmation

Simple form	V-ing form
I could mystify you could mystify she could mystify we could mystify you could mystify they could mystify	I could be mystifying you could be mystifying she 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 she 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 she 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 she 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 she 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 she 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 she 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 she mystify? could we mystify? could you mystify? could they mystify?	could I be mystifying? could you be mystifying? could she 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 she 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 she 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 she 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 she 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 she 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 she have been mystifying? couldn't we have been mystifying? couldn't you have been mystifying? couldn't they have been mystifying?