English verb conjugation
CAN UNDERLINE

Regular verb: underline - underlined - underlined

Affirmation

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

Negation

Simple form	V-ing form
I cannot underline you cannot underline she cannot underline we cannot underline you cannot underline they cannot underline	I cannot be underlining you cannot be underlining she cannot be underlining we cannot be underlining you cannot be underlining they cannot be underlining
Perfect	V-ing perfect
I cannot have underlined you cannot have underlined she cannot have underlined we cannot have underlined you cannot have underlined they cannot have underlined	I cannot have been underlining you cannot have been underlining she cannot have been underlining we cannot have been underlining you cannot have been underlining they cannot have been underlining

Interrogative form

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

Interro-negative form

Simple form	V-ing form
can I not underline? can you not underline? can she not underline? can we not underline? can you not underline? can they not underline?	can I not be underlining? can you not be underlining? can she not be underlining? can we not be underlining? can you not be underlining? can they not be underlining?
Perfect	V-ing perfect
can I not have underlined? can you not have underlined? can she not have underlined? can we not have underlined? can you not have underlined? can they not have underlined?	can I not have been underlining? can you not have been underlining? can she not have been underlining? can we not have been underlining? can you not have been underlining? can they not have been underlining?