foolproof

1. ADJ Something such as a plan or a machine that is foolproof is so well designed, easy to understand, or easy to use that it cannot go wrong or be used wrongly. 不出問題的; 不會(huì)弄錯(cuò)的

The system is not 100 per cent foolproof. 該系統(tǒng)不是百分之百不出毛病的。