a belt-and-braces policy的用法和样例：
- Readers who click through are taken to a document that is comfortingly entitled “Belt and Braces”.
- You don't need braces if you're wearing a belt!
- My trousers only stay up if I wear a belt.
- You wear a belt with gadgets and mini tools.
- My shirt hikes up if I don't wear a belt.
- Really?! What does it say about clothing? I bought a belt and sandals with sea shells on them, they're just so elegant!