I'd be fastening you'd be fastening he'd be fastening we'd be fastening you'd be fastening they'd be fastening
Perfect
I should've fastened you should've fastened he should've fastened we should've fastened you should've fastened they should've fastened
V-ing perfect
I should've been fastening you should've been fastening he should've been fastening we should've been fastening you should've been fastening they should've been fastening
Negation
Simple form
I shouldn't fasten you shouldn't fasten he shouldn't fasten we shouldn't fasten you shouldn't fasten they shouldn't fasten
V-ing form
I shouldn't be fastening you shouldn't be fastening he shouldn't be fastening we shouldn't be fastening you shouldn't be fastening they shouldn't be fastening
Perfect
I shouldn't have fastened you shouldn't have fastened he shouldn't have fastened we shouldn't have fastened you shouldn't have fastened they shouldn't have fastened
V-ing perfect
I shouldn't have been fastening you shouldn't have been fastening he shouldn't have been fastening we shouldn't have been fastening you shouldn't have been fastening they shouldn't have been fastening
Interrogative form
Simple form
should I fasten? should you fasten? should he fasten? should we fasten? should you fasten? should they fasten?
V-ing form
should I be fastening? should you be fastening? should he be fastening? should we be fastening? should you be fastening? should they be fastening?
Perfect
should I have fastened? should you have fastened? should he have fastened? should we have fastened? should you have fastened? should they have fastened?
V-ing perfect
should I have been fastening? should you have been fastening? should he have been fastening? should we have been fastening? should you have been fastening? should they have been fastening?
Interro-negative form
Simple form
shouldn't I fasten? shouldn't you fasten? shouldn't he fasten? shouldn't we fasten? shouldn't you fasten? shouldn't they fasten?
V-ing form
shouldn't I be fastening? shouldn't you be fastening? shouldn't he be fastening? shouldn't we be fastening? shouldn't you be fastening? shouldn't they be fastening?
Perfect
shouldn't I have fastened? shouldn't you have fastened? shouldn't he have fastened? shouldn't we have fastened? shouldn't you have fastened? shouldn't they have fastened?
V-ing perfect
shouldn't I have been fastening? shouldn't you have been fastening? shouldn't he have been fastening? shouldn't we have been fastening? shouldn't you have been fastening? shouldn't they have been fastening?