It was a place impossible to enter except on official business, and then only by penetrating through a maze of barbed-wire entanglements, steel doors, and hidden machine-gun nests.

• 除非公干，谁也别想进去； 即便进得去，也必得先穿过迷宫似的铁丝网、铁门，外加隐蔽的机枪掩体。