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