  We present a possible understanding to the issues of cosmological constant,
inflation, matter and coincidence problems based only on the Einstein equation
and Hawking particle production. The inflation appears and results agree to
observations. The CMB large-scale anomaly can be explained and the dark-matter
acoustic wave is speculated. The entropy and reheating are discussed. The
cosmological term $\Omega_{_\Lambda}$ tracks down the matter $\Omega_{_M}$
until the radiation-matter equilibrium, then slowly varies, thus the cosmic
coincidence problem can be avoided. The relation between $\Omega_{_\Lambda}$
and $\Omega_{_M}$ is shown and can be examined at large redshifts.
