Should 与 must, have to 的区别

should 表达行为的道德义务。不应用于表达行为的法定义务。为了表达采取肯定行动（命令或要求）的法律义务，使用 must或have to。

should expresses moral duty to act. Should cannot be used to express legal duty to act. To express legal duty to act in the affirmative (command or requirement), use must or have to.

“You must / have to file a response to the complaint within 30 days of receipt.”

To express legal duty to refrain from acting, in other words, prohibition from acting use must not or may not.