  In this paper, the one-loop CHY-integrands of bi-adjoint scalar theory has
been reinvestigated. Differing from previous constructions, we have explicitly
removed contributions from tadpole and massless bubbles when taking the forward
limit of corresponding tree-level amplitudes. The way to remove those singular
contributions is to exploit the idea of 'picking poles', which is to multiply a
special cross ratio factor with the role of isolating terms having a particular
pole structure.
