English verb conjugation
CAN DOUBT

Regular verb: doubt - doubted - doubted

Affirmation

Simple form	V-ing form
I can doubt you can doubt he can doubt we can doubt you can doubt they can doubt	I can be doubting you can be doubting he can be doubting we can be doubting you can be doubting they can be doubting
Perfect	V-ing perfect
I can have doubted you can have doubted he can have doubted we can have doubted you can have doubted they can have doubted	I can have been doubting you can have been doubting he can have been doubting we can have been doubting you can have been doubting they can have been doubting

Negation

Simple form	V-ing form
I cannot doubt you cannot doubt he cannot doubt we cannot doubt you cannot doubt they cannot doubt	I cannot be doubting you cannot be doubting he cannot be doubting we cannot be doubting you cannot be doubting they cannot be doubting
Perfect	V-ing perfect
I cannot have doubted you cannot have doubted he cannot have doubted we cannot have doubted you cannot have doubted they cannot have doubted	I cannot have been doubting you cannot have been doubting he cannot have been doubting we cannot have been doubting you cannot have been doubting they cannot have been doubting

Interrogative form

Simple form	V-ing form
can I doubt? can you doubt? can he doubt? can we doubt? can you doubt? can they doubt?	can I be doubting? can you be doubting? can he be doubting? can we be doubting? can you be doubting? can they be doubting?
Perfect	V-ing perfect
can I have doubted? can you have doubted? can he have doubted? can we have doubted? can you have doubted? can they have doubted?	can I have been doubting? can you have been doubting? can he have been doubting? can we have been doubting? can you have been doubting? can they have been doubting?

Interro-negative form

Simple form	V-ing form
can I not doubt? can you not doubt? can he not doubt? can we not doubt? can you not doubt? can they not doubt?	can I not be doubting? can you not be doubting? can he not be doubting? can we not be doubting? can you not be doubting? can they not be doubting?
Perfect	V-ing perfect
can I not have doubted? can you not have doubted? can he not have doubted? can we not have doubted? can you not have doubted? can they not have doubted?	can I not have been doubting? can you not have been doubting? can he not have been doubting? can we not have been doubting? can you not have been doubting? can they not have been doubting?