English verb conjugation
COULD TREMBLE

Regular verb: tremble - trembled - trembled

Affirmation

Simple form	V-ing form
I could tremble you could tremble she could tremble we could tremble you could tremble they could tremble	I could be trembling you could be trembling she could be trembling we could be trembling you could be trembling they could be trembling
Perfect	V-ing perfect
I could have trembled you could have trembled she could have trembled we could have trembled you could have trembled they could have trembled	I could have been trembling you could have been trembling she could have been trembling we could have been trembling you could have been trembling they could have been trembling

Negation

Simple form	V-ing form
I could not tremble you could not tremble she could not tremble we could not tremble you could not tremble they could not tremble	I could not be trembling you could not be trembling she could not be trembling we could not be trembling you could not be trembling they could not be trembling
Perfect	V-ing perfect
I could not have trembled you could not have trembled she could not have trembled we could not have trembled you could not have trembled they could not have trembled	I could not have been trembling you could not have been trembling she could not have been trembling we could not have been trembling you could not have been trembling they could not have been trembling

Interrogative form

Simple form	V-ing form
could I tremble? could you tremble? could she tremble? could we tremble? could you tremble? could they tremble?	could I be trembling? could you be trembling? could she be trembling? could we be trembling? could you be trembling? could they be trembling?
Perfect	V-ing perfect
could I have trembled? could you have trembled? could she have trembled? could we have trembled? could you have trembled? could they have trembled?	could I have been trembling? could you have been trembling? could she have been trembling? could we have been trembling? could you have been trembling? could they have been trembling?

Interro-negative form

Simple form	V-ing form
could I not tremble? could you not tremble? could she not tremble? could we not tremble? could you not tremble? could they not tremble?	could I not be trembling? could you not be trembling? could she not be trembling? could we not be trembling? could you not be trembling? could they not be trembling?
Perfect	V-ing perfect
could I not have trembled? could you not have trembled? could she not have trembled? could we not have trembled? could you not have trembled? could they not have trembled?	could I not have been trembling? could you not have been trembling? could she not have been trembling? could we not have been trembling? could you not have been trembling? could they not have been trembling?