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