English verb conjugation
CAN TOUGH

Regular verb: tough - toughed - toughed

Affirmation

Simple form	V-ing form
I can tough you can tough he can tough we can tough you can tough they can tough	I can be toughing you can be toughing he can be toughing we can be toughing you can be toughing they can be toughing
Perfect	V-ing perfect
I can have toughed you can have toughed he can have toughed we can have toughed you can have toughed they can have toughed	I can have been toughing you can have been toughing he can have been toughing we can have been toughing you can have been toughing they can have been toughing

Negation

Simple form	V-ing form
I cannot tough you cannot tough he cannot tough we cannot tough you cannot tough they cannot tough	I cannot be toughing you cannot be toughing he cannot be toughing we cannot be toughing you cannot be toughing they cannot be toughing
Perfect	V-ing perfect
I cannot have toughed you cannot have toughed he cannot have toughed we cannot have toughed you cannot have toughed they cannot have toughed	I cannot have been toughing you cannot have been toughing he cannot have been toughing we cannot have been toughing you cannot have been toughing they cannot have been toughing

Interrogative form

Simple form	V-ing form
can I tough? can you tough? can he tough? can we tough? can you tough? can they tough?	can I be toughing? can you be toughing? can he be toughing? can we be toughing? can you be toughing? can they be toughing?
Perfect	V-ing perfect
can I have toughed? can you have toughed? can he have toughed? can we have toughed? can you have toughed? can they have toughed?	can I have been toughing? can you have been toughing? can he have been toughing? can we have been toughing? can you have been toughing? can they have been toughing?

Interro-negative form

Simple form	V-ing form
can I not tough? can you not tough? can he not tough? can we not tough? can you not tough? can they not tough?	can I not be toughing? can you not be toughing? can he not be toughing? can we not be toughing? can you not be toughing? can they not be toughing?
Perfect	V-ing perfect
can I not have toughed? can you not have toughed? can he not have toughed? can we not have toughed? can you not have toughed? can they not have toughed?	can I not have been toughing? can you not have been toughing? can he not have been toughing? can we not have been toughing? can you not have been toughing? can they not have been toughing?