I
would have double-checked
you
would have double-checked
he / she / it
would have double-checked
we
would have double-checked
you
would have double-checked
they
would have double-checked
I
would have been double-checking
you
would have been double-checking
he / she / it
would have been double-checking
we
would have been double-checking
you
would have been double-checking
they
would have been double-checking