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