I could spring you could spring he could spring we could spring you could spring they could spring
V-ing form
I could be springing you could be springing he could be springing we could be springing you could be springing they could be springing
Perfect
I could have sprung you could have sprung he could have sprung we could have sprung you could have sprung they could have sprung
V-ing perfect
I could have been springing you could have been springing he could have been springing we could have been springing you could have been springing they could have been springing
Negation
Simple form
I could not spring you could not spring he could not spring we could not spring you could not spring they could not spring
V-ing form
I could not be springing you could not be springing he could not be springing we could not be springing you could not be springing they could not be springing
Perfect
I could not have sprung you could not have sprung he could not have sprung we could not have sprung you could not have sprung they could not have sprung
V-ing perfect
I could not have been springing you could not have been springing he could not have been springing we could not have been springing you could not have been springing they could not have been springing
Interrogative form
Simple form
could I spring? could you spring? could he spring? could we spring? could you spring? could they spring?
V-ing form
could I be springing? could you be springing? could he be springing? could we be springing? could you be springing? could they be springing?
Perfect
could I have sprung? could you have sprung? could he have sprung? could we have sprung? could you have sprung? could they have sprung?
V-ing perfect
could I have been springing? could you have been springing? could he have been springing? could we have been springing? could you have been springing? could they have been springing?
Interro-negative form
Simple form
could I not spring? could you not spring? could he not spring? could we not spring? could you not spring? could they not spring?
V-ing form
could I not be springing? could you not be springing? could he not be springing? could we not be springing? could you not be springing? could they not be springing?
Perfect
could I not have sprung? could you not have sprung? could he not have sprung? could we not have sprung? could you not have sprung? could they not have sprung?
V-ing perfect
could I not have been springing? could you not have been springing? could he not have been springing? could we not have been springing? could you not have been springing? could they not have been springing?