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