English verb conjugation
CAN TOUGH

Regular verb: tough - toughed - toughed

Affirmation

Simple form	V-ing form
I can tough you can tough she can tough we can tough you can tough they can tough	I can be toughing you can be toughing she 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 she 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 she 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 she cannot tough we cannot tough you cannot tough they cannot tough	I cannot be toughing you cannot be toughing she 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 she 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 she 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 she tough? can we tough? can you tough? can they tough?	can I be toughing? can you be toughing? can she 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 she 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 she 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 she 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 she 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 she 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 she not have been toughing? can we not have been toughing? can you not have been toughing? can they not have been toughing?