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