I could lightning you could lightning he could lightning we could lightning you could lightning they could lightning
V-ing form
I could be lightninging you could be lightninging he could be lightninging we could be lightninging you could be lightninging they could be lightninging
Perfect
I could have lightninged you could have lightninged he could have lightninged we could have lightninged you could have lightninged they could have lightninged
V-ing perfect
I could have been lightninging you could have been lightninging he could have been lightninging we could have been lightninging you could have been lightninging they could have been lightninging
Negation
Simple form
I could not lightning you could not lightning he could not lightning we could not lightning you could not lightning they could not lightning
V-ing form
I could not be lightninging you could not be lightninging he could not be lightninging we could not be lightninging you could not be lightninging they could not be lightninging
Perfect
I could not have lightninged you could not have lightninged he could not have lightninged we could not have lightninged you could not have lightninged they could not have lightninged
V-ing perfect
I could not have been lightninging you could not have been lightninging he could not have been lightninging we could not have been lightninging you could not have been lightninging they could not have been lightninging
Interrogative form
Simple form
could I lightning? could you lightning? could he lightning? could we lightning? could you lightning? could they lightning?
V-ing form
could I be lightninging? could you be lightninging? could he be lightninging? could we be lightninging? could you be lightninging? could they be lightninging?
Perfect
could I have lightninged? could you have lightninged? could he have lightninged? could we have lightninged? could you have lightninged? could they have lightninged?
V-ing perfect
could I have been lightninging? could you have been lightninging? could he have been lightninging? could we have been lightninging? could you have been lightninging? could they have been lightninging?
Interro-negative form
Simple form
could I not lightning? could you not lightning? could he not lightning? could we not lightning? could you not lightning? could they not lightning?
V-ing form
could I not be lightninging? could you not be lightninging? could he not be lightninging? could we not be lightninging? could you not be lightninging? could they not be lightninging?
Perfect
could I not have lightninged? could you not have lightninged? could he not have lightninged? could we not have lightninged? could you not have lightninged? could they not have lightninged?
V-ing perfect
could I not have been lightninging? could you not have been lightninging? could he not have been lightninging? could we not have been lightninging? could you not have been lightninging? could they not have been lightninging?