❶outpost ❷advance guard 在月球上建立一个～，作为在火星上登陆之用的中间整备区域establish a lunar outpost to serve as a staging area for a Martian landing/社会主义的～outpost of socialism/双方的～advance guards of the two sides/外交工作的～ outpost of diplomacy/与敌人～接触skirmish with the enemy’s advance guards/～战skirmish