不敢越雷池一步原指不要越过雷池。后比喻不敢超越一定的范围和界限。雷池：湖名，在安徽省望江县南。

出自晋·庾亮《报温峤书》：“吾忧西陲，过于历阳，足下无过雷池一步也。” 

那么不敢越雷池一步用英语怎么说？

不敢越雷池一步可以用dare not go one step beyond the prescribed limit来表示，例如：

1.我们为什么要墨守成规，不敢越雷池一步呢？
Why do we have to stick to conventions and dare not go one step beyond the prescribed limit? 

2.我的一位朋友就不幸地经历过此事，从次他们再也不敢越雷池一步了。
I've had friends who have suffered this misfortune and have since sworn that they will never again cross that friendship boundary. 

3.这条分界线不知比原来的大路宽了多少倍，没有学生敢越雷池一步，包括他们和她们的目光，青春的诗情画意在现实的腐朽中埋没得连气都不敢大声喘息。
But the boundary was much wider than the original road, nobody dared to cross even to be close to it, which include not only their bodies but also their sights. 

4.树生长缓慢，如果你因为害怕摔下去而不敢越雷池一步的话，你将没有机会目睹享受森林多彩而绚丽的生活。
The downside is, trees grow slowly and if you never leave the tree for fear of falling, you'll never see all the amazing life and color in the rest of the forest. 

5.在1914年12月24日，英德两军分别在各自相对安全的战壕中对峙，谁都不敢越雷池一步。
On December 24th ,1914, German and English troops faced each other from the relative safety of their ditches across which no man's land lying between them.

你可能还想知道：不敢苟同用英语怎么说？