bastionofiron铜墙铁壁
boilerwall;锅炉壁
cellwall细胞壁
aprecipitouscliff;precipice;峭壁
unscalablecliff绝壁
strengthenthedefencesandclearthefields;坚壁清野
watchthefightingfromtheramparts;beanonlooker作壁上观
(anindependent)sectionofacountry半壁江山
BiMing壁明
〈名〉
〈动〉