English verb conjugation
COULD ISOLATE

Regular verb: isolate - isolated - isolated

Affirmation

Simple form	V-ing form
I could isolate you could isolate he could isolate we could isolate you could isolate they could isolate	I could be isolating you could be isolating he could be isolating we could be isolating you could be isolating they could be isolating
Perfect	V-ing perfect
I could have isolated you could have isolated he could have isolated we could have isolated you could have isolated they could have isolated	I could have been isolating you could have been isolating he could have been isolating we could have been isolating you could have been isolating they could have been isolating

Negation

Simple form	V-ing form
I couldn't isolate you couldn't isolate he couldn't isolate we couldn't isolate you couldn't isolate they couldn't isolate	I couldn't be isolating you couldn't be isolating he couldn't be isolating we couldn't be isolating you couldn't be isolating they couldn't be isolating
Perfect	V-ing perfect
I couldn't have isolated you couldn't have isolated he couldn't have isolated we couldn't have isolated you couldn't have isolated they couldn't have isolated	I couldn't have been isolating you couldn't have been isolating he couldn't have been isolating we couldn't have been isolating you couldn't have been isolating they couldn't have been isolating

Interrogative form

Simple form	V-ing form
could I isolate? could you isolate? could he isolate? could we isolate? could you isolate? could they isolate?	could I be isolating? could you be isolating? could he be isolating? could we be isolating? could you be isolating? could they be isolating?
Perfect	V-ing perfect
could I have isolated? could you have isolated? could he have isolated? could we have isolated? could you have isolated? could they have isolated?	could I have been isolating? could you have been isolating? could he have been isolating? could we have been isolating? could you have been isolating? could they have been isolating?

Interro-negative form

Simple form	V-ing form
couldn't I isolate? couldn't you isolate? couldn't he isolate? couldn't we isolate? couldn't you isolate? couldn't they isolate?	couldn't I be isolating? couldn't you be isolating? couldn't he be isolating? couldn't we be isolating? couldn't you be isolating? couldn't they be isolating?
Perfect	V-ing perfect
couldn't I have isolated? couldn't you have isolated? couldn't he have isolated? couldn't we have isolated? couldn't you have isolated? couldn't they have isolated?	couldn't I have been isolating? couldn't you have been isolating? couldn't he have been isolating? couldn't we have been isolating? couldn't you have been isolating? couldn't they have been isolating?