adj [attrib 作定语] (of equipment, machinery, etc) designed to compensate automatically for a breakdown or failure （指设备、机器等）设有自动保险装置的
*the fail-safe mechanism 自动保险机械装置.
a fail-safe machine, piece of equipment etc contains a system that makes the machine stop working if one part of it fails
a fail-safe plan is certain to succeed
1. Even if a piped water supply is safe at its source, it is not always safe by the time it reaches the tap. 即使管道供水系统在水源处安全的，等水到达龙头时就不一定总是安全的了。
2. But he still did not feel safe enough. 可是他还觉得不够安全.
3. Bonpland was doubtful whether, even then, it was safe. 即使如此，庞普朗还是怀疑这水是否安全。
4. Because it was embarrassing to fail every time, he stopped checking the man when he crossed. 一次次检查都找不出什么，这挺令人尴尬的，他也就不再在那司机过境时检查了。
5. When lights fuse, furniture gets rickety, pipes get clogged, or vacuum cleaners fail to operate, 每当电灯保险丝烧断、家具榫头松动、管道堵塞、吸尘器不动时，
6. Would she fail again? 这次它会不会又一次失败？
7. When the bear was gone, and all was safe, the man in the tree came down. 熊走了，一切都平安无事了。树上的人爬了下来，
8. While active, child-bearing age women are most likely to have low iron stores, he notes, "Men are not safe, especially if they don't eat meat and have a high level of physical activity." 他还指出，虽然积极锻炼的育龄妇女最有可能铁离子储量低，"但男性也并非不缺铁，尤其是在他们不吃肉类而又从事高强度的体力活动的情况下。"
9. There is no safe landing on that coast. 那一带海岸没有安全的登陆处.
10. The safe had been rifled and many documents taken. 保险箱遭到搜劫, 许多文件被盗走了.