ní wǎ jiàng / zài / qì qiáng / shí / bì xū / bǎo zhèng / měi céng / qì céng / de / hòu dù / yí zhì泥瓦匠在砌墙时必须保证每层砌层的厚度一致。A mason must ensure that each course of brickwork has consistent thickness.