English verb conjugation
COULD HUM

Regular verb: hum - humed - humed

Affirmation

Simple form	V-ing form
I could hum you could hum he could hum we could hum you could hum they could hum	I could be huming you could be huming he could be huming we could be huming you could be huming they could be huming
Perfect	V-ing perfect
I could have humed you could have humed he could have humed we could have humed you could have humed they could have humed	I could have been huming you could have been huming he could have been huming we could have been huming you could have been huming they could have been huming

Negation

Simple form	V-ing form
I couldn't hum you couldn't hum he couldn't hum we couldn't hum you couldn't hum they couldn't hum	I couldn't be huming you couldn't be huming he couldn't be huming we couldn't be huming you couldn't be huming they couldn't be huming
Perfect	V-ing perfect
I couldn't have humed you couldn't have humed he couldn't have humed we couldn't have humed you couldn't have humed they couldn't have humed	I couldn't have been huming you couldn't have been huming he couldn't have been huming we couldn't have been huming you couldn't have been huming they couldn't have been huming

Interrogative form

Simple form	V-ing form
could I hum? could you hum? could he hum? could we hum? could you hum? could they hum?	could I be huming? could you be huming? could he be huming? could we be huming? could you be huming? could they be huming?
Perfect	V-ing perfect
could I have humed? could you have humed? could he have humed? could we have humed? could you have humed? could they have humed?	could I have been huming? could you have been huming? could he have been huming? could we have been huming? could you have been huming? could they have been huming?

Interro-negative form

Simple form	V-ing form
couldn't I hum? couldn't you hum? couldn't he hum? couldn't we hum? couldn't you hum? couldn't they hum?	couldn't I be huming? couldn't you be huming? couldn't he be huming? couldn't we be huming? couldn't you be huming? couldn't they be huming?
Perfect	V-ing perfect
couldn't I have humed? couldn't you have humed? couldn't he have humed? couldn't we have humed? couldn't you have humed? couldn't they have humed?	couldn't I have been huming? couldn't you have been huming? couldn't he have been huming? couldn't we have been huming? couldn't you have been huming? couldn't they have been huming?