This recipe is foolproof ─ it works every time.

　　這個食譜絕對管用，每次都萬無一失。

　　The system is not 100 per cent foolproof

　　這個系統并非是萬無一失。

　　I spent the day working out a foolproof plan to save him.

　　我花了一天的時間想出了一個營救他的周全方案。

　　Always ensure you have a foolproof way to get paid.

　　永遠確保你拿得到錢。

　　This new system is supposed to be foolproof.

　　據說這個新系統不會出毛病。