English verb conjugation
COULD FAST

Regular verb: fast - fasted - fasted

Affirmation

Simple form	V-ing form
I could fast you could fast he could fast we could fast you could fast they could fast	I could be fasting you could be fasting he could be fasting we could be fasting you could be fasting they could be fasting
Perfect	V-ing perfect
I could have fasted you could have fasted he could have fasted we could have fasted you could have fasted they could have fasted	I could have been fasting you could have been fasting he could have been fasting we could have been fasting you could have been fasting they could have been fasting

Negation

Simple form	V-ing form
I couldn't fast you couldn't fast he couldn't fast we couldn't fast you couldn't fast they couldn't fast	I couldn't be fasting you couldn't be fasting he couldn't be fasting we couldn't be fasting you couldn't be fasting they couldn't be fasting
Perfect	V-ing perfect
I couldn't have fasted you couldn't have fasted he couldn't have fasted we couldn't have fasted you couldn't have fasted they couldn't have fasted	I couldn't have been fasting you couldn't have been fasting he couldn't have been fasting we couldn't have been fasting you couldn't have been fasting they couldn't have been fasting

Interrogative form

Simple form	V-ing form
could I fast? could you fast? could he fast? could we fast? could you fast? could they fast?	could I be fasting? could you be fasting? could he be fasting? could we be fasting? could you be fasting? could they be fasting?
Perfect	V-ing perfect
could I have fasted? could you have fasted? could he have fasted? could we have fasted? could you have fasted? could they have fasted?	could I have been fasting? could you have been fasting? could he have been fasting? could we have been fasting? could you have been fasting? could they have been fasting?

Interro-negative form

Simple form	V-ing form
couldn't I fast? couldn't you fast? couldn't he fast? couldn't we fast? couldn't you fast? couldn't they fast?	couldn't I be fasting? couldn't you be fasting? couldn't he be fasting? couldn't we be fasting? couldn't you be fasting? couldn't they be fasting?
Perfect	V-ing perfect
couldn't I have fasted? couldn't you have fasted? couldn't he have fasted? couldn't we have fasted? couldn't you have fasted? couldn't they have fasted?	couldn't I have been fasting? couldn't you have been fasting? couldn't he have been fasting? couldn't we have been fasting? couldn't you have been fasting? couldn't they have been fasting?