English verb conjugation
CAN FASTEN

Regular verb: fasten - fastened - fastened

Affirmation

Simple form	V-ing form
I can fasten you can fasten he can fasten we can fasten you can fasten they can fasten	I can be fastening you can be fastening he can be fastening we can be fastening you can be fastening they can be fastening
Perfect	V-ing perfect
I can have fastened you can have fastened he can have fastened we can have fastened you can have fastened they can have fastened	I can have been fastening you can have been fastening he can have been fastening we can have been fastening you can have been fastening they can have been fastening

Negation

Simple form	V-ing form
I cannot fasten you cannot fasten he cannot fasten we cannot fasten you cannot fasten they cannot fasten	I cannot be fastening you cannot be fastening he cannot be fastening we cannot be fastening you cannot be fastening they cannot be fastening
Perfect	V-ing perfect
I cannot have fastened you cannot have fastened he cannot have fastened we cannot have fastened you cannot have fastened they cannot have fastened	I cannot have been fastening you cannot have been fastening he cannot have been fastening we cannot have been fastening you cannot have been fastening they cannot have been fastening

Interrogative form

Simple form	V-ing form
can I fasten? can you fasten? can he fasten? can we fasten? can you fasten? can they fasten?	can I be fastening? can you be fastening? can he be fastening? can we be fastening? can you be fastening? can they be fastening?
Perfect	V-ing perfect
can I have fastened? can you have fastened? can he have fastened? can we have fastened? can you have fastened? can they have fastened?	can I have been fastening? can you have been fastening? can he have been fastening? can we have been fastening? can you have been fastening? can they have been fastening?

Interro-negative form

Simple form	V-ing form
can I not fasten? can you not fasten? can he not fasten? can we not fasten? can you not fasten? can they not fasten?	can I not be fastening? can you not be fastening? can he not be fastening? can we not be fastening? can you not be fastening? can they not be fastening?
Perfect	V-ing perfect
can I not have fastened? can you not have fastened? can he not have fastened? can we not have fastened? can you not have fastened? can they not have fastened?	can I not have been fastening? can you not have been fastening? can he not have been fastening? can we not have been fastening? can you not have been fastening? can they not have been fastening?