English verb conjugation
COULD UNDERLINE

Regular verb: underline - underlined - underlined

Affirmation

Simple form	V-ing form
I could underline you could underline he could underline we could underline you could underline they could underline	I could be underlining you could be underlining he could be underlining we could be underlining you could be underlining they could be underlining
Perfect	V-ing perfect
I could have underlined you could have underlined he could have underlined we could have underlined you could have underlined they could have underlined	I could have been underlining you could have been underlining he could have been underlining we could have been underlining you could have been underlining they could have been underlining

Negation

Simple form	V-ing form
I couldn't underline you couldn't underline he couldn't underline we couldn't underline you couldn't underline they couldn't underline	I couldn't be underlining you couldn't be underlining he couldn't be underlining we couldn't be underlining you couldn't be underlining they couldn't be underlining
Perfect	V-ing perfect
I couldn't have underlined you couldn't have underlined he couldn't have underlined we couldn't have underlined you couldn't have underlined they couldn't have underlined	I couldn't have been underlining you couldn't have been underlining he couldn't have been underlining we couldn't have been underlining you couldn't have been underlining they couldn't have been underlining

Interrogative form

Simple form	V-ing form
could I underline? could you underline? could he underline? could we underline? could you underline? could they underline?	could I be underlining? could you be underlining? could he be underlining? could we be underlining? could you be underlining? could they be underlining?
Perfect	V-ing perfect
could I have underlined? could you have underlined? could he have underlined? could we have underlined? could you have underlined? could they have underlined?	could I have been underlining? could you have been underlining? could he have been underlining? could we have been underlining? could you have been underlining? could they have been underlining?

Interro-negative form

Simple form	V-ing form
couldn't I underline? couldn't you underline? couldn't he underline? couldn't we underline? couldn't you underline? couldn't they underline?	couldn't I be underlining? couldn't you be underlining? couldn't he be underlining? couldn't we be underlining? couldn't you be underlining? couldn't they be underlining?
Perfect	V-ing perfect
couldn't I have underlined? couldn't you have underlined? couldn't he have underlined? couldn't we have underlined? couldn't you have underlined? couldn't they have underlined?	couldn't I have been underlining? couldn't you have been underlining? couldn't he have been underlining? couldn't we have been underlining? couldn't you have been underlining? couldn't they have been underlining?