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