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