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