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