English verb conjugation
COULD DRAIN

Regular verb: drain - drained - drained

Affirmation

Simple form	V-ing form
I could drain you could drain he could drain we could drain you could drain they could drain	I could be draining you could be draining he could be draining we could be draining you could be draining they could be draining
Perfect	V-ing perfect
I could have drained you could have drained he could have drained we could have drained you could have drained they could have drained	I could have been draining you could have been draining he could have been draining we could have been draining you could have been draining they could have been draining

Negation

Simple form	V-ing form
I couldn't drain you couldn't drain he couldn't drain we couldn't drain you couldn't drain they couldn't drain	I couldn't be draining you couldn't be draining he couldn't be draining we couldn't be draining you couldn't be draining they couldn't be draining
Perfect	V-ing perfect
I couldn't have drained you couldn't have drained he couldn't have drained we couldn't have drained you couldn't have drained they couldn't have drained	I couldn't have been draining you couldn't have been draining he couldn't have been draining we couldn't have been draining you couldn't have been draining they couldn't have been draining

Interrogative form

Simple form	V-ing form
could I drain? could you drain? could he drain? could we drain? could you drain? could they drain?	could I be draining? could you be draining? could he be draining? could we be draining? could you be draining? could they be draining?
Perfect	V-ing perfect
could I have drained? could you have drained? could he have drained? could we have drained? could you have drained? could they have drained?	could I have been draining? could you have been draining? could he have been draining? could we have been draining? could you have been draining? could they have been draining?

Interro-negative form

Simple form	V-ing form
couldn't I drain? couldn't you drain? couldn't he drain? couldn't we drain? couldn't you drain? couldn't they drain?	couldn't I be draining? couldn't you be draining? couldn't he be draining? couldn't we be draining? couldn't you be draining? couldn't they be draining?
Perfect	V-ing perfect
couldn't I have drained? couldn't you have drained? couldn't he have drained? couldn't we have drained? couldn't you have drained? couldn't they have drained?	couldn't I have been draining? couldn't you have been draining? couldn't he have been draining? couldn't we have been draining? couldn't you have been draining? couldn't they have been draining?