to secretly replace a crucial component with an inferior one; to practice surreptitious substitution or deception; to substitute the fake for the genuine.
为了降低成本，一些不良商家会抽梁换柱，用劣质材料冒充优质品。
To cut down costs, some unscrupulous businesses would practice surreptitious substitution, using inferior materials to pass off as high-quality goods.
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