English verb conjugation
COULD PRESERVE

Regular verb: preserve - preserved - preserved

Affirmation

Simple form	V-ing form
I could preserve you could preserve he could preserve we could preserve you could preserve they could preserve	I could be preserving you could be preserving he could be preserving we could be preserving you could be preserving they could be preserving
Perfect	V-ing perfect
I could have preserved you could have preserved he could have preserved we could have preserved you could have preserved they could have preserved	I could have been preserving you could have been preserving he could have been preserving we could have been preserving you could have been preserving they could have been preserving

Negation

Simple form	V-ing form
I could not preserve you could not preserve he could not preserve we could not preserve you could not preserve they could not preserve	I could not be preserving you could not be preserving he could not be preserving we could not be preserving you could not be preserving they could not be preserving
Perfect	V-ing perfect
I could not have preserved you could not have preserved he could not have preserved we could not have preserved you could not have preserved they could not have preserved	I could not have been preserving you could not have been preserving he could not have been preserving we could not have been preserving you could not have been preserving they could not have been preserving

Interrogative form

Simple form	V-ing form
could I preserve? could you preserve? could he preserve? could we preserve? could you preserve? could they preserve?	could I be preserving? could you be preserving? could he be preserving? could we be preserving? could you be preserving? could they be preserving?
Perfect	V-ing perfect
could I have preserved? could you have preserved? could he have preserved? could we have preserved? could you have preserved? could they have preserved?	could I have been preserving? could you have been preserving? could he have been preserving? could we have been preserving? could you have been preserving? could they have been preserving?

Interro-negative form

Simple form	V-ing form
could I not preserve? could you not preserve? could he not preserve? could we not preserve? could you not preserve? could they not preserve?	could I not be preserving? could you not be preserving? could he not be preserving? could we not be preserving? could you not be preserving? could they not be preserving?
Perfect	V-ing perfect
could I not have preserved? could you not have preserved? could he not have preserved? could we not have preserved? could you not have preserved? could they not have preserved?	could I not have been preserving? could you not have been preserving? could he not have been preserving? could we not have been preserving? could you not have been preserving? could they not have been preserving?