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