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