English verb conjugation
COULD SIGNAL

Regular verb: signal - signalled - signalled

Affirmation

Simple form	V-ing form
I could signal you could signal he could signal we could signal you could signal they could signal	I could be signalling you could be signalling he could be signalling we could be signalling you could be signalling they could be signalling
Perfect	V-ing perfect
I could have signalled you could have signalled he could have signalled we could have signalled you could have signalled they could have signalled	I could have been signalling you could have been signalling he could have been signalling we could have been signalling you could have been signalling they could have been signalling

Negation

Simple form	V-ing form
I could not signal you could not signal he could not signal we could not signal you could not signal they could not signal	I could not be signalling you could not be signalling he could not be signalling we could not be signalling you could not be signalling they could not be signalling
Perfect	V-ing perfect
I could not have signalled you could not have signalled he could not have signalled we could not have signalled you could not have signalled they could not have signalled	I could not have been signalling you could not have been signalling he could not have been signalling we could not have been signalling you could not have been signalling they could not have been signalling

Interrogative form

Simple form	V-ing form
could I signal? could you signal? could he signal? could we signal? could you signal? could they signal?	could I be signalling? could you be signalling? could he be signalling? could we be signalling? could you be signalling? could they be signalling?
Perfect	V-ing perfect
could I have signalled? could you have signalled? could he have signalled? could we have signalled? could you have signalled? could they have signalled?	could I have been signalling? could you have been signalling? could he have been signalling? could we have been signalling? could you have been signalling? could they have been signalling?

Interro-negative form

Simple form	V-ing form
could I not signal? could you not signal? could he not signal? could we not signal? could you not signal? could they not signal?	could I not be signalling? could you not be signalling? could he not be signalling? could we not be signalling? could you not be signalling? could they not be signalling?
Perfect	V-ing perfect
could I not have signalled? could you not have signalled? could he not have signalled? could we not have signalled? could you not have signalled? could they not have signalled?	could I not have been signalling? could you not have been signalling? could he not have been signalling? could we not have been signalling? could you not have been signalling? could they not have been signalling?