English verb conjugation
COULD RIVET

Regular verb: rivet - riveted - riveted

Affirmation

Simple form	V-ing form
I could rivet you could rivet he could rivet we could rivet you could rivet they could rivet	I could be riveting you could be riveting he could be riveting we could be riveting you could be riveting they could be riveting
Perfect	V-ing perfect
I could have riveted you could have riveted he could have riveted we could have riveted you could have riveted they could have riveted	I could have been riveting you could have been riveting he could have been riveting we could have been riveting you could have been riveting they could have been riveting

Negation

Simple form	V-ing form
I couldn't rivet you couldn't rivet he couldn't rivet we couldn't rivet you couldn't rivet they couldn't rivet	I couldn't be riveting you couldn't be riveting he couldn't be riveting we couldn't be riveting you couldn't be riveting they couldn't be riveting
Perfect	V-ing perfect
I couldn't have riveted you couldn't have riveted he couldn't have riveted we couldn't have riveted you couldn't have riveted they couldn't have riveted	I couldn't have been riveting you couldn't have been riveting he couldn't have been riveting we couldn't have been riveting you couldn't have been riveting they couldn't have been riveting

Interrogative form

Simple form	V-ing form
could I rivet? could you rivet? could he rivet? could we rivet? could you rivet? could they rivet?	could I be riveting? could you be riveting? could he be riveting? could we be riveting? could you be riveting? could they be riveting?
Perfect	V-ing perfect
could I have riveted? could you have riveted? could he have riveted? could we have riveted? could you have riveted? could they have riveted?	could I have been riveting? could you have been riveting? could he have been riveting? could we have been riveting? could you have been riveting? could they have been riveting?

Interro-negative form

Simple form	V-ing form
couldn't I rivet? couldn't you rivet? couldn't he rivet? couldn't we rivet? couldn't you rivet? couldn't they rivet?	couldn't I be riveting? couldn't you be riveting? couldn't he be riveting? couldn't we be riveting? couldn't you be riveting? couldn't they be riveting?
Perfect	V-ing perfect
couldn't I have riveted? couldn't you have riveted? couldn't he have riveted? couldn't we have riveted? couldn't you have riveted? couldn't they have riveted?	couldn't I have been riveting? couldn't you have been riveting? couldn't he have been riveting? couldn't we have been riveting? couldn't you have been riveting? couldn't they have been riveting?