她在手提包的底部加了一些硬衬，让它更挺括。

She added some ___stiffeners to the bottom of the handbag to make it more structured.

为了增加浓稠度，这瓶胶水中添加了增稠剂。

This bottle of glue contains ___stiffeners to increase its thickness.

工程师在建筑结构中添加了金属加强筋以提高稳定性。

Engineers added metal ___stiffeners to the structure to enhance its stability.