未经培训就操作这台机器简直就是找死。

Operating this machine without training is a real ___widowmaker.

徒步时我们避开那些随时可能倒下、被称为‘寡妇制造者’的危险枯树。

While hiking, we avoided the dangerous dead trees known as ___widowmakers that could fall at any moment.

医生告诉他，那条堵塞的主要动脉可能致命。

The doctor told him that the blocked main artery was a potential ___widowmaker.