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