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