壁垒森严

closely guarded
strongly fortified
sharply divided

壁挂, 闭关政策, 闭关自守, 闭合, 壁虎, 避讳, 壁画, 璧还, 闭会, 闭会祈祷, 哔叽, 壁架, 必将, 闭经, 毕竟, 壁龛, 避坑落井, 碧蓝, 避雷器, 壁垒, 壁立, 贲临, 壁炉, 秘鲁, 碧绿, 蓖麻, 闭门思过, 闭门造车, 避免, 毙命, 闭幕, 闭目塞听, 避难所, 避难, 睥睨, 婢女, 毕其功于一役, 避其锐气/击其惰归, 必然, 闭塞,