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