I could loosen you could loosen he could loosen we could loosen you could loosen they could loosen
V-ing form
I could be loosening you could be loosening he could be loosening we could be loosening you could be loosening they could be loosening
Perfect
I could have loosened you could have loosened he could have loosened we could have loosened you could have loosened they could have loosened
V-ing perfect
I could have been loosening you could have been loosening he could have been loosening we could have been loosening you could have been loosening they could have been loosening
Negation
Simple form
I couldn't loosen you couldn't loosen he couldn't loosen we couldn't loosen you couldn't loosen they couldn't loosen
V-ing form
I couldn't be loosening you couldn't be loosening he couldn't be loosening we couldn't be loosening you couldn't be loosening they couldn't be loosening
Perfect
I couldn't have loosened you couldn't have loosened he couldn't have loosened we couldn't have loosened you couldn't have loosened they couldn't have loosened
V-ing perfect
I couldn't have been loosening you couldn't have been loosening he couldn't have been loosening we couldn't have been loosening you couldn't have been loosening they couldn't have been loosening
Interrogative form
Simple form
could I loosen? could you loosen? could he loosen? could we loosen? could you loosen? could they loosen?
V-ing form
could I be loosening? could you be loosening? could he be loosening? could we be loosening? could you be loosening? could they be loosening?
Perfect
could I have loosened? could you have loosened? could he have loosened? could we have loosened? could you have loosened? could they have loosened?
V-ing perfect
could I have been loosening? could you have been loosening? could he have been loosening? could we have been loosening? could you have been loosening? could they have been loosening?
Interro-negative form
Simple form
couldn't I loosen? couldn't you loosen? couldn't he loosen? couldn't we loosen? couldn't you loosen? couldn't they loosen?
V-ing form
couldn't I be loosening? couldn't you be loosening? couldn't he be loosening? couldn't we be loosening? couldn't you be loosening? couldn't they be loosening?
Perfect
couldn't I have loosened? couldn't you have loosened? couldn't he have loosened? couldn't we have loosened? couldn't you have loosened? couldn't they have loosened?
V-ing perfect
couldn't I have been loosening? couldn't you have been loosening? couldn't he have been loosening? couldn't we have been loosening? couldn't you have been loosening? couldn't they have been loosening?