English verb conjugation
COULD EXSERT

Regular verb: exsert - exserted - exserted

Affirmation

Simple form	V-ing form
I could exsert you could exsert she could exsert we could exsert you could exsert they could exsert	I could be exserting you could be exserting she could be exserting we could be exserting you could be exserting they could be exserting
Perfect	V-ing perfect
I could have exserted you could have exserted she could have exserted we could have exserted you could have exserted they could have exserted	I could have been exserting you could have been exserting she could have been exserting we could have been exserting you could have been exserting they could have been exserting

Negation

Simple form	V-ing form
I couldn't exsert you couldn't exsert she couldn't exsert we couldn't exsert you couldn't exsert they couldn't exsert	I couldn't be exserting you couldn't be exserting she couldn't be exserting we couldn't be exserting you couldn't be exserting they couldn't be exserting
Perfect	V-ing perfect
I couldn't have exserted you couldn't have exserted she couldn't have exserted we couldn't have exserted you couldn't have exserted they couldn't have exserted	I couldn't have been exserting you couldn't have been exserting she couldn't have been exserting we couldn't have been exserting you couldn't have been exserting they couldn't have been exserting

Interrogative form

Simple form	V-ing form
could I exsert? could you exsert? could she exsert? could we exsert? could you exsert? could they exsert?	could I be exserting? could you be exserting? could she be exserting? could we be exserting? could you be exserting? could they be exserting?
Perfect	V-ing perfect
could I have exserted? could you have exserted? could she have exserted? could we have exserted? could you have exserted? could they have exserted?	could I have been exserting? could you have been exserting? could she have been exserting? could we have been exserting? could you have been exserting? could they have been exserting?

Interro-negative form

Simple form	V-ing form
couldn't I exsert? couldn't you exsert? couldn't she exsert? couldn't we exsert? couldn't you exsert? couldn't they exsert?	couldn't I be exserting? couldn't you be exserting? couldn't she be exserting? couldn't we be exserting? couldn't you be exserting? couldn't they be exserting?
Perfect	V-ing perfect
couldn't I have exserted? couldn't you have exserted? couldn't she have exserted? couldn't we have exserted? couldn't you have exserted? couldn't they have exserted?	couldn't I have been exserting? couldn't you have been exserting? couldn't she have been exserting? couldn't we have been exserting? couldn't you have been exserting? couldn't they have been exserting?