English verb conjugation
COULD CLENCH

Regular verb: clench - clenched - clenched

Affirmation

Simple form	V-ing form
I could clench you could clench he could clench we could clench you could clench they could clench	I could be clenching you could be clenching he could be clenching we could be clenching you could be clenching they could be clenching
Perfect	V-ing perfect
I could have clenched you could have clenched he could have clenched we could have clenched you could have clenched they could have clenched	I could have been clenching you could have been clenching he could have been clenching we could have been clenching you could have been clenching they could have been clenching

Negation

Simple form	V-ing form
I could not clench you could not clench he could not clench we could not clench you could not clench they could not clench	I could not be clenching you could not be clenching he could not be clenching we could not be clenching you could not be clenching they could not be clenching
Perfect	V-ing perfect
I could not have clenched you could not have clenched he could not have clenched we could not have clenched you could not have clenched they could not have clenched	I could not have been clenching you could not have been clenching he could not have been clenching we could not have been clenching you could not have been clenching they could not have been clenching

Interrogative form

Simple form	V-ing form
could I clench? could you clench? could he clench? could we clench? could you clench? could they clench?	could I be clenching? could you be clenching? could he be clenching? could we be clenching? could you be clenching? could they be clenching?
Perfect	V-ing perfect
could I have clenched? could you have clenched? could he have clenched? could we have clenched? could you have clenched? could they have clenched?	could I have been clenching? could you have been clenching? could he have been clenching? could we have been clenching? could you have been clenching? could they have been clenching?

Interro-negative form

Simple form	V-ing form
could I not clench? could you not clench? could he not clench? could we not clench? could you not clench? could they not clench?	could I not be clenching? could you not be clenching? could he not be clenching? could we not be clenching? could you not be clenching? could they not be clenching?
Perfect	V-ing perfect
could I not have clenched? could you not have clenched? could he not have clenched? could we not have clenched? could you not have clenched? could they not have clenched?	could I not have been clenching? could you not have been clenching? could he not have been clenching? could we not have been clenching? could you not have been clenching? could they not have been clenching?