Complex sentence: Soldiers located at these three garrisons are considered to be the cream of the PLA, but are not permitted to leave their compounds, even during off-duty times to mingle with the local populace.
Split into simpler sentences: Soldiers located at these three garrisons are considered to be the cream of the PLA. The soldiers are not permitted to leave their compounds, even during off-duty times to mingle with the local populace.