English verb conjugation
COULD MARBLE

Regular verb: marble - marbled - marbled

Affirmation

Simple form	V-ing form
I could marble you could marble he could marble we could marble you could marble they could marble	I could be marbling you could be marbling he could be marbling we could be marbling you could be marbling they could be marbling
Perfect	V-ing perfect
I could have marbled you could have marbled he could have marbled we could have marbled you could have marbled they could have marbled	I could have been marbling you could have been marbling he could have been marbling we could have been marbling you could have been marbling they could have been marbling

Negation

Simple form	V-ing form
I couldn't marble you couldn't marble he couldn't marble we couldn't marble you couldn't marble they couldn't marble	I couldn't be marbling you couldn't be marbling he couldn't be marbling we couldn't be marbling you couldn't be marbling they couldn't be marbling
Perfect	V-ing perfect
I couldn't have marbled you couldn't have marbled he couldn't have marbled we couldn't have marbled you couldn't have marbled they couldn't have marbled	I couldn't have been marbling you couldn't have been marbling he couldn't have been marbling we couldn't have been marbling you couldn't have been marbling they couldn't have been marbling

Interrogative form

Simple form	V-ing form
could I marble? could you marble? could he marble? could we marble? could you marble? could they marble?	could I be marbling? could you be marbling? could he be marbling? could we be marbling? could you be marbling? could they be marbling?
Perfect	V-ing perfect
could I have marbled? could you have marbled? could he have marbled? could we have marbled? could you have marbled? could they have marbled?	could I have been marbling? could you have been marbling? could he have been marbling? could we have been marbling? could you have been marbling? could they have been marbling?

Interro-negative form

Simple form	V-ing form
couldn't I marble? couldn't you marble? couldn't he marble? couldn't we marble? couldn't you marble? couldn't they marble?	couldn't I be marbling? couldn't you be marbling? couldn't he be marbling? couldn't we be marbling? couldn't you be marbling? couldn't they be marbling?
Perfect	V-ing perfect
couldn't I have marbled? couldn't you have marbled? couldn't he have marbled? couldn't we have marbled? couldn't you have marbled? couldn't they have marbled?	couldn't I have been marbling? couldn't you have been marbling? couldn't he have been marbling? couldn't we have been marbling? couldn't you have been marbling? couldn't they have been marbling?