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