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