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