  The parton and hadron cascade model PACIAE is used to simulate the 0-6,
15-25, and 35-45 % most central Au+Au collisions at \sqrt{s_{NN}}=19.6, 62.4,
130, and 200 GeV and the 0-10 % most central Pb+Pb collisions at
\sqrt{s_{NN}}=5500 GeV. The calculated charged multiplicity and the charged
particle transverse momentum distribution, pseudorapidity distribution, and
extended longitudinal scaling for Au+Au collisions well agree with the
corresponding PHOBOS data. Thus the above observables calculated for Pb+Pb
collisions would be a reliable prediction.
