English verb conjugation
COULD THRESH

Regular verb: thresh - threshed - threshed

Affirmation

Simple form	V-ing form
I could thresh you could thresh she could thresh we could thresh you could thresh they could thresh	I could be threshing you could be threshing she could be threshing we could be threshing you could be threshing they could be threshing
Perfect	V-ing perfect
I could have threshed you could have threshed she could have threshed we could have threshed you could have threshed they could have threshed	I could have been threshing you could have been threshing she could have been threshing we could have been threshing you could have been threshing they could have been threshing

Negation

Simple form	V-ing form
I couldn't thresh you couldn't thresh she couldn't thresh we couldn't thresh you couldn't thresh they couldn't thresh	I couldn't be threshing you couldn't be threshing she couldn't be threshing we couldn't be threshing you couldn't be threshing they couldn't be threshing
Perfect	V-ing perfect
I couldn't have threshed you couldn't have threshed she couldn't have threshed we couldn't have threshed you couldn't have threshed they couldn't have threshed	I couldn't have been threshing you couldn't have been threshing she couldn't have been threshing we couldn't have been threshing you couldn't have been threshing they couldn't have been threshing

Interrogative form

Simple form	V-ing form
could I thresh? could you thresh? could she thresh? could we thresh? could you thresh? could they thresh?	could I be threshing? could you be threshing? could she be threshing? could we be threshing? could you be threshing? could they be threshing?
Perfect	V-ing perfect
could I have threshed? could you have threshed? could she have threshed? could we have threshed? could you have threshed? could they have threshed?	could I have been threshing? could you have been threshing? could she have been threshing? could we have been threshing? could you have been threshing? could they have been threshing?

Interro-negative form

Simple form	V-ing form
couldn't I thresh? couldn't you thresh? couldn't she thresh? couldn't we thresh? couldn't you thresh? couldn't they thresh?	couldn't I be threshing? couldn't you be threshing? couldn't she be threshing? couldn't we be threshing? couldn't you be threshing? couldn't they be threshing?
Perfect	V-ing perfect
couldn't I have threshed? couldn't you have threshed? couldn't she have threshed? couldn't we have threshed? couldn't you have threshed? couldn't they have threshed?	couldn't I have been threshing? couldn't you have been threshing? couldn't she have been threshing? couldn't we have been threshing? couldn't you have been threshing? couldn't they have been threshing?