English verb conjugation
COULD EXSERT

Regular verb: exsert - exserted - exserted

Affirmation

Simple form	V-ing form
I could exsert you could exsert he could exsert we could exsert you could exsert they could exsert	I could be exserting you could be exserting he 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 he 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 he 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 could not exsert you could not exsert he could not exsert we could not exsert you could not exsert they could not exsert	I could not be exserting you could not be exserting he could not be exserting we could not be exserting you could not be exserting they could not be exserting
Perfect	V-ing perfect
I could not have exserted you could not have exserted he could not have exserted we could not have exserted you could not have exserted they could not have exserted	I could not have been exserting you could not have been exserting he could not have been exserting we could not have been exserting you could not have been exserting they could not have been exserting

Interrogative form

Simple form	V-ing form
could I exsert? could you exsert? could he exsert? could we exsert? could you exsert? could they exsert?	could I be exserting? could you be exserting? could he 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 he 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 he 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
could I not exsert? could you not exsert? could he not exsert? could we not exsert? could you not exsert? could they not exsert?	could I not be exserting? could you not be exserting? could he not be exserting? could we not be exserting? could you not be exserting? could they not be exserting?
Perfect	V-ing perfect
could I not have exserted? could you not have exserted? could he not have exserted? could we not have exserted? could you not have exserted? could they not have exserted?	could I not have been exserting? could you not have been exserting? could he not have been exserting? could we not have been exserting? could you not have been exserting? could they not have been exserting?