那简直是最纯粹的疯狂，他竟然在大冬天跳进冰湖里。

It was the ___sheer madness that he jumped into the frozen lake in winter.

她的成功完全是勤奋工作和全心投入的结果。

Her success was the ___sheer result of hard work and dedication.

窗帘是用最轻薄的布料做的，几乎透明。

The curtains were made of the ___sheerest fabric, almost transparent.