I could codify you could codify she could codify we could codify you could codify they could codify
V-ing form
I could be codifying you could be codifying she could be codifying we could be codifying you could be codifying they could be codifying
Perfect
I could have codified you could have codified she could have codified we could have codified you could have codified they could have codified
V-ing perfect
I could have been codifying you could have been codifying she could have been codifying we could have been codifying you could have been codifying they could have been codifying
Negation
Simple form
I couldn't codify you couldn't codify she couldn't codify we couldn't codify you couldn't codify they couldn't codify
V-ing form
I couldn't be codifying you couldn't be codifying she couldn't be codifying we couldn't be codifying you couldn't be codifying they couldn't be codifying
Perfect
I couldn't have codified you couldn't have codified she couldn't have codified we couldn't have codified you couldn't have codified they couldn't have codified
V-ing perfect
I couldn't have been codifying you couldn't have been codifying she couldn't have been codifying we couldn't have been codifying you couldn't have been codifying they couldn't have been codifying
Interrogative form
Simple form
could I codify? could you codify? could she codify? could we codify? could you codify? could they codify?
V-ing form
could I be codifying? could you be codifying? could she be codifying? could we be codifying? could you be codifying? could they be codifying?
Perfect
could I have codified? could you have codified? could she have codified? could we have codified? could you have codified? could they have codified?
V-ing perfect
could I have been codifying? could you have been codifying? could she have been codifying? could we have been codifying? could you have been codifying? could they have been codifying?
Interro-negative form
Simple form
couldn't I codify? couldn't you codify? couldn't she codify? couldn't we codify? couldn't you codify? couldn't they codify?
V-ing form
couldn't I be codifying? couldn't you be codifying? couldn't she be codifying? couldn't we be codifying? couldn't you be codifying? couldn't they be codifying?
Perfect
couldn't I have codified? couldn't you have codified? couldn't she have codified? couldn't we have codified? couldn't you have codified? couldn't they have codified?
V-ing perfect
couldn't I have been codifying? couldn't you have been codifying? couldn't she have been codifying? couldn't we have been codifying? couldn't you have been codifying? couldn't they have been codifying?