  We propose a simple implementation scheme of quantum delayed-choice
experiment in linear optical system without initial entanglement resource. By
choosing different detecting devices, one can selectively observe the photon's
different behaviors after the photon has been passed the Mach-Zehnder
interferometer. The scheme shows that the photon's wave behavior and particle
behavior can be observed with a single experimental setup by postselection,
that is, the photon can show the superposition behavior of wave and particle.
Especially, we compare the wave-particle superposition behavior and the
wave-particle mixture behavior in detail, and find the quantum interference
effect between wave and particle behavior, which may be helpful to reveal the
nature of photon essentially.
