hard rule

that's a hard rule. that's a rough rule.

真是一个很难的规则。真是一个很粗糙的规则。

the general rule is to raise the wrist for the pinky and lower it to play the thumb. of course, this is not a hard rule;

一般的规则是用到小指的时候抬高手腕，弹拇指的时候压低手腕。当然，这不是绝对的规则；

that whole thing about priests not being allowed to repeat what they hear in confessions, is that a hard rule, or just a general guideline?

关于牧师不允许重复他们在忏悔里所听到的话，是一条强硬的规则还是只是个一般性的指导方针？

this is a hard rule to follow.

这个规则看来很难遵守。

if there's one hard rule of childhood, it's that kids don't like fish.

要说童年有什么不变的规律，那就是孩子们都不喜欢吃鱼。

no hard rule dictates how long a line of code should be.

没有硬性规定一个代码行应该多长。

it is better to have a soft rule that is roughly right than a hard rule that makes no economic sense.

但一个基本正确的软性准则总比一个没有经济意义的硬性规定来的强。

the only hard rule the couple have to stick by is the 40 mile per hour speed limit the 83-year old car is restricted to.

这对夫妇唯一必须要坚持的硬性规定就是这辆“83岁”的老车时速限制在40英里以内。