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