表达 “once bitten, twice shy” 的意思是 “在第一次做某件事情时，有了不愉快的经历，因此第二次再做时会害怕、小心或忧虑”，类似于汉语里说的 “一朝被蛇咬，十年怕井绳”。

例句
Since Debbie broke up with her boyfriend, she’s become very cautious about starting a new relationship. It’s a case of once bitten, twice shy.
自从黛比和男友分手之后，对于开展新的恋情就变得很犹豫。真是一朝被蛇咬，十年怕井绳。

After Fangfang was sick on the rollercoaster, I don’t think she’ll go on one again – once bitten, twice shy!
在芳芳上次坐过山车感觉恶心吐了之后，我看她不敢再坐了 —— 俗话说：一朝被蛇咬，十年怕井绳！

I tried eating a bowl of very spicy noodles – wow, it was hot. So I’ll go for something milder next time. Once bitten, twice shy!
我尝了一碗特别辣的面条，哇噻，可真够辣的。下次我会吃味淡一点的东西。正所谓一次被咬，下次胆小！