English verb conjugation
COULD GRAB

Regular verb: grab - grabbed - grabbed

Affirmation

Simple form	V-ing form
I could grab you could grab he could grab we could grab you could grab they could grab	I could be grabbing you could be grabbing he could be grabbing we could be grabbing you could be grabbing they could be grabbing
Perfect	V-ing perfect
I could have grabbed you could have grabbed he could have grabbed we could have grabbed you could have grabbed they could have grabbed	I could have been grabbing you could have been grabbing he could have been grabbing we could have been grabbing you could have been grabbing they could have been grabbing

Negation

Simple form	V-ing form
I couldn't grab you couldn't grab he couldn't grab we couldn't grab you couldn't grab they couldn't grab	I couldn't be grabbing you couldn't be grabbing he couldn't be grabbing we couldn't be grabbing you couldn't be grabbing they couldn't be grabbing
Perfect	V-ing perfect
I couldn't have grabbed you couldn't have grabbed he couldn't have grabbed we couldn't have grabbed you couldn't have grabbed they couldn't have grabbed	I couldn't have been grabbing you couldn't have been grabbing he couldn't have been grabbing we couldn't have been grabbing you couldn't have been grabbing they couldn't have been grabbing

Interrogative form

Simple form	V-ing form
could I grab? could you grab? could he grab? could we grab? could you grab? could they grab?	could I be grabbing? could you be grabbing? could he be grabbing? could we be grabbing? could you be grabbing? could they be grabbing?
Perfect	V-ing perfect
could I have grabbed? could you have grabbed? could he have grabbed? could we have grabbed? could you have grabbed? could they have grabbed?	could I have been grabbing? could you have been grabbing? could he have been grabbing? could we have been grabbing? could you have been grabbing? could they have been grabbing?

Interro-negative form

Simple form	V-ing form
couldn't I grab? couldn't you grab? couldn't he grab? couldn't we grab? couldn't you grab? couldn't they grab?	couldn't I be grabbing? couldn't you be grabbing? couldn't he be grabbing? couldn't we be grabbing? couldn't you be grabbing? couldn't they be grabbing?
Perfect	V-ing perfect
couldn't I have grabbed? couldn't you have grabbed? couldn't he have grabbed? couldn't we have grabbed? couldn't you have grabbed? couldn't they have grabbed?	couldn't I have been grabbing? couldn't you have been grabbing? couldn't he have been grabbing? couldn't we have been grabbing? couldn't you have been grabbing? couldn't they have been grabbing?