I could lean you could lean she could lean we could lean you could lean they could lean
V-ing form
I could be leaning you could be leaning she could be leaning we could be leaning you could be leaning they could be leaning
Perfect
I could have leaned you could have leaned she could have leaned we could have leaned you could have leaned they could have leaned
V-ing perfect
I could have been leaning you could have been leaning she could have been leaning we could have been leaning you could have been leaning they could have been leaning
Negation
Simple form
I couldn't lean you couldn't lean she couldn't lean we couldn't lean you couldn't lean they couldn't lean
V-ing form
I couldn't be leaning you couldn't be leaning she couldn't be leaning we couldn't be leaning you couldn't be leaning they couldn't be leaning
Perfect
I couldn't have leaned you couldn't have leaned she couldn't have leaned we couldn't have leaned you couldn't have leaned they couldn't have leaned
V-ing perfect
I couldn't have been leaning you couldn't have been leaning she couldn't have been leaning we couldn't have been leaning you couldn't have been leaning they couldn't have been leaning
Interrogative form
Simple form
could I lean? could you lean? could she lean? could we lean? could you lean? could they lean?
V-ing form
could I be leaning? could you be leaning? could she be leaning? could we be leaning? could you be leaning? could they be leaning?
Perfect
could I have leaned? could you have leaned? could she have leaned? could we have leaned? could you have leaned? could they have leaned?
V-ing perfect
could I have been leaning? could you have been leaning? could she have been leaning? could we have been leaning? could you have been leaning? could they have been leaning?
Interro-negative form
Simple form
couldn't I lean? couldn't you lean? couldn't she lean? couldn't we lean? couldn't you lean? couldn't they lean?
V-ing form
couldn't I be leaning? couldn't you be leaning? couldn't she be leaning? couldn't we be leaning? couldn't you be leaning? couldn't they be leaning?
Perfect
couldn't I have leaned? couldn't you have leaned? couldn't she have leaned? couldn't we have leaned? couldn't you have leaned? couldn't they have leaned?
V-ing perfect
couldn't I have been leaning? couldn't you have been leaning? couldn't she have been leaning? couldn't we have been leaning? couldn't you have been leaning? couldn't they have been leaning?