I could cling you could cling he could cling we could cling you could cling they could cling
V-ing form
I could be clinging you could be clinging he could be clinging we could be clinging you could be clinging they could be clinging
Perfect
I could have clung you could have clung he could have clung we could have clung you could have clung they could have clung
V-ing perfect
I could have been clinging you could have been clinging he could have been clinging we could have been clinging you could have been clinging they could have been clinging
Negation
Simple form
I could not cling you could not cling he could not cling we could not cling you could not cling they could not cling
V-ing form
I could not be clinging you could not be clinging he could not be clinging we could not be clinging you could not be clinging they could not be clinging
Perfect
I could not have clung you could not have clung he could not have clung we could not have clung you could not have clung they could not have clung
V-ing perfect
I could not have been clinging you could not have been clinging he could not have been clinging we could not have been clinging you could not have been clinging they could not have been clinging
Interrogative form
Simple form
could I cling? could you cling? could he cling? could we cling? could you cling? could they cling?
V-ing form
could I be clinging? could you be clinging? could he be clinging? could we be clinging? could you be clinging? could they be clinging?
Perfect
could I have clung? could you have clung? could he have clung? could we have clung? could you have clung? could they have clung?
V-ing perfect
could I have been clinging? could you have been clinging? could he have been clinging? could we have been clinging? could you have been clinging? could they have been clinging?
Interro-negative form
Simple form
could I not cling? could you not cling? could he not cling? could we not cling? could you not cling? could they not cling?
V-ing form
could I not be clinging? could you not be clinging? could he not be clinging? could we not be clinging? could you not be clinging? could they not be clinging?
Perfect
could I not have clung? could you not have clung? could he not have clung? could we not have clung? could you not have clung? could they not have clung?
V-ing perfect
could I not have been clinging? could you not have been clinging? could he not have been clinging? could we not have been clinging? could you not have been clinging? could they not have been clinging?