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