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