English verb conjugation
CAN CHALLENGE

Regular verb: challenge - challenged - challenged

Affirmation

Simple form	V-ing form
I can challenge you can challenge he can challenge we can challenge you can challenge they can challenge	I can be challenging you can be challenging he can be challenging we can be challenging you can be challenging they can be challenging
Perfect	V-ing perfect
I can have challenged you can have challenged he can have challenged we can have challenged you can have challenged they can have challenged	I can have been challenging you can have been challenging he can have been challenging we can have been challenging you can have been challenging they can have been challenging

Negation

Simple form	V-ing form
I can't challenge you can't challenge he can't challenge we can't challenge you can't challenge they can't challenge	I can't be challenging you can't be challenging he can't be challenging we can't be challenging you can't be challenging they can't be challenging
Perfect	V-ing perfect
I can't have challenged you can't have challenged he can't have challenged we can't have challenged you can't have challenged they can't have challenged	I can't have been challenging you can't have been challenging he can't have been challenging we can't have been challenging you can't have been challenging they can't have been challenging

Interrogative form

Simple form	V-ing form
can I challenge? can you challenge? can he challenge? can we challenge? can you challenge? can they challenge?	can I be challenging? can you be challenging? can he be challenging? can we be challenging? can you be challenging? can they be challenging?
Perfect	V-ing perfect
can I have challenged? can you have challenged? can he have challenged? can we have challenged? can you have challenged? can they have challenged?	can I have been challenging? can you have been challenging? can he have been challenging? can we have been challenging? can you have been challenging? can they have been challenging?

Interro-negative form

Simple form	V-ing form
can't I challenge? can't you challenge? can't he challenge? can't we challenge? can't you challenge? can't they challenge?	can't I be challenging? can't you be challenging? can't he be challenging? can't we be challenging? can't you be challenging? can't they be challenging?
Perfect	V-ing perfect
can't I have challenged? can't you have challenged? can't he have challenged? can't we have challenged? can't you have challenged? can't they have challenged?	can't I have been challenging? can't you have been challenging? can't he have been challenging? can't we have been challenging? can't you have been challenging? can't they have been challenging?