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