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 couldn't cling you couldn't cling he couldn't cling we couldn't cling you couldn't cling they couldn't cling
V-ing form
I couldn't be clinging you couldn't be clinging he couldn't be clinging we couldn't be clinging you couldn't be clinging they couldn't be clinging
Perfect
I couldn't have clung you couldn't have clung he couldn't have clung we couldn't have clung you couldn't have clung they couldn't have clung
V-ing perfect
I couldn't have been clinging you couldn't have been clinging he couldn't have been clinging we couldn't have been clinging you couldn't have been clinging they couldn't 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
couldn't I cling? couldn't you cling? couldn't he cling? couldn't we cling? couldn't you cling? couldn't they cling?
V-ing form
couldn't I be clinging? couldn't you be clinging? couldn't he be clinging? couldn't we be clinging? couldn't you be clinging? couldn't they be clinging?
Perfect
couldn't I have clung? couldn't you have clung? couldn't he have clung? couldn't we have clung? couldn't you have clung? couldn't they have clung?
V-ing perfect
couldn't I have been clinging? couldn't you have been clinging? couldn't he have been clinging? couldn't we have been clinging? couldn't you have been clinging? couldn't they have been clinging?