I could quiet you could quiet he could quiet we could quiet you could quiet they could quiet
V-ing form
I could be quieting you could be quieting he could be quieting we could be quieting you could be quieting they could be quieting
Perfect
I could have quieted you could have quieted he could have quieted we could have quieted you could have quieted they could have quieted
V-ing perfect
I could have been quieting you could have been quieting he could have been quieting we could have been quieting you could have been quieting they could have been quieting
Negation
Simple form
I couldn't quiet you couldn't quiet he couldn't quiet we couldn't quiet you couldn't quiet they couldn't quiet
V-ing form
I couldn't be quieting you couldn't be quieting he couldn't be quieting we couldn't be quieting you couldn't be quieting they couldn't be quieting
Perfect
I couldn't have quieted you couldn't have quieted he couldn't have quieted we couldn't have quieted you couldn't have quieted they couldn't have quieted
V-ing perfect
I couldn't have been quieting you couldn't have been quieting he couldn't have been quieting we couldn't have been quieting you couldn't have been quieting they couldn't have been quieting
Interrogative form
Simple form
could I quiet? could you quiet? could he quiet? could we quiet? could you quiet? could they quiet?
V-ing form
could I be quieting? could you be quieting? could he be quieting? could we be quieting? could you be quieting? could they be quieting?
Perfect
could I have quieted? could you have quieted? could he have quieted? could we have quieted? could you have quieted? could they have quieted?
V-ing perfect
could I have been quieting? could you have been quieting? could he have been quieting? could we have been quieting? could you have been quieting? could they have been quieting?
Interro-negative form
Simple form
couldn't I quiet? couldn't you quiet? couldn't he quiet? couldn't we quiet? couldn't you quiet? couldn't they quiet?
V-ing form
couldn't I be quieting? couldn't you be quieting? couldn't he be quieting? couldn't we be quieting? couldn't you be quieting? couldn't they be quieting?
Perfect
couldn't I have quieted? couldn't you have quieted? couldn't he have quieted? couldn't we have quieted? couldn't you have quieted? couldn't they have quieted?
V-ing perfect
couldn't I have been quieting? couldn't you have been quieting? couldn't he have been quieting? couldn't we have been quieting? couldn't you have been quieting? couldn't they have been quieting?