I could quest you could quest she could quest we could quest you could quest they could quest
V-ing form
I could be questing you could be questing she could be questing we could be questing you could be questing they could be questing
Perfect
I could have quested you could have quested she could have quested we could have quested you could have quested they could have quested
V-ing perfect
I could have been questing you could have been questing she could have been questing we could have been questing you could have been questing they could have been questing
Negation
Simple form
I could not quest you could not quest she could not quest we could not quest you could not quest they could not quest
V-ing form
I could not be questing you could not be questing she could not be questing we could not be questing you could not be questing they could not be questing
Perfect
I could not have quested you could not have quested she could not have quested we could not have quested you could not have quested they could not have quested
V-ing perfect
I could not have been questing you could not have been questing she could not have been questing we could not have been questing you could not have been questing they could not have been questing
Interrogative form
Simple form
could I quest? could you quest? could she quest? could we quest? could you quest? could they quest?
V-ing form
could I be questing? could you be questing? could she be questing? could we be questing? could you be questing? could they be questing?
Perfect
could I have quested? could you have quested? could she have quested? could we have quested? could you have quested? could they have quested?
V-ing perfect
could I have been questing? could you have been questing? could she have been questing? could we have been questing? could you have been questing? could they have been questing?
Interro-negative form
Simple form
could I not quest? could you not quest? could she not quest? could we not quest? could you not quest? could they not quest?
V-ing form
could I not be questing? could you not be questing? could she not be questing? could we not be questing? could you not be questing? could they not be questing?
Perfect
could I not have quested? could you not have quested? could she not have quested? could we not have quested? could you not have quested? could they not have quested?
V-ing perfect
could I not have been questing? could you not have been questing? could she not have been questing? could we not have been questing? could you not have been questing? could they not have been questing?