English verb conjugation
CAN FROWN

Regular verb: frown - frowned - frowned

Affirmation

Simple form	V-ing form
I can frown you can frown he can frown we can frown you can frown they can frown	I can be frowning you can be frowning he can be frowning we can be frowning you can be frowning they can be frowning
Perfect	V-ing perfect
I can have frowned you can have frowned he can have frowned we can have frowned you can have frowned they can have frowned	I can have been frowning you can have been frowning he can have been frowning we can have been frowning you can have been frowning they can have been frowning

Negation

Simple form	V-ing form
I cannot frown you cannot frown he cannot frown we cannot frown you cannot frown they cannot frown	I cannot be frowning you cannot be frowning he cannot be frowning we cannot be frowning you cannot be frowning they cannot be frowning
Perfect	V-ing perfect
I cannot have frowned you cannot have frowned he cannot have frowned we cannot have frowned you cannot have frowned they cannot have frowned	I cannot have been frowning you cannot have been frowning he cannot have been frowning we cannot have been frowning you cannot have been frowning they cannot have been frowning

Interrogative form

Simple form	V-ing form
can I frown? can you frown? can he frown? can we frown? can you frown? can they frown?	can I be frowning? can you be frowning? can he be frowning? can we be frowning? can you be frowning? can they be frowning?
Perfect	V-ing perfect
can I have frowned? can you have frowned? can he have frowned? can we have frowned? can you have frowned? can they have frowned?	can I have been frowning? can you have been frowning? can he have been frowning? can we have been frowning? can you have been frowning? can they have been frowning?

Interro-negative form

Simple form	V-ing form
can I not frown? can you not frown? can he not frown? can we not frown? can you not frown? can they not frown?	can I not be frowning? can you not be frowning? can he not be frowning? can we not be frowning? can you not be frowning? can they not be frowning?
Perfect	V-ing perfect
can I not have frowned? can you not have frowned? can he not have frowned? can we not have frowned? can you not have frowned? can they not have frowned?	can I not have been frowning? can you not have been frowning? can he not have been frowning? can we not have been frowning? can you not have been frowning? can they not have been frowning?