{"id":273332,"date":"2026-09-13T03:01:07","date_gmt":"2026-09-13T08:01:07","guid":{"rendered":"https:\/\/langcom.org\/?p=273332"},"modified":"2026-09-13T03:01:07","modified_gmt":"2026-09-13T08:01:07","slug":"obligation-permission-b2-grammar-b2","status":"publish","type":"post","link":"https:\/\/langcom.org\/zh\/blog\/obligation-permission-b2-grammar-b2\/","title":{"rendered":"\u638c\u63e1\u82f1\u8bed\u4e2d\u7684\u4e49\u52a1\u4e0e\u8bb8\u53ef\uff08B2\u7ea7\u8bed\u6cd5\uff09"},"content":{"rendered":"
To express obligation or permission in English, we use a variety of modal verbs and phrases, each with specific nuances depending on the situation and the speaker’s perspective.<\/strong> For strong obligations, we often use must<\/span> \u6216 have to<\/span>, with must<\/span> typically indicating a personal or internal rule, and have to<\/span> suggesting an external rule or necessity. For advice or weaker obligation, should<\/span> \u6216 ought to<\/span> are common. When there is no obligation, we say don’t have to<\/span> \u6216 don’t need to<\/span>. For permission, can<\/span> \u548c be allowed to<\/span> are frequently used, while mustn’t<\/span> \u6216 can’t<\/span> indicate prohibition. Understanding these differences is key to communicating clearly and correctly in English.<\/div>\n

What Do Obligation and Permission Mean?<\/h2>\n

In English grammar, ‘obligation’ refers to something you must do, or something that is necessary. It’s a duty or a requirement.<\/p>\n

‘Permission’ means you are allowed to do something. It’s the opposite of prohibition.<\/p>\n

\u270d\ufe0f \u4e0d\u786e\u5b9a\u81ea\u5df1\u7684\u6c34\u5e73\u5982\u4f55\uff1f<\/h3>

\u53c2\u52a0\u6211\u4eec\u7684\u514d\u8d39\u5206\u7ea7\u6d4b\u8bd5\uff0c\u83b7\u5f97\u7531\u5251\u6865\u8ba4\u8bc1\u8003\u5b98\u63d0\u4f9b\u7684\u4e2a\u6027\u5316\u53cd\u9988\u3002.<\/p>\u53c2\u52a0\u6211\u4eec\u7684\u514d\u8d39\u5206\u7ea7\u6d4b\u8bd5<\/a><\/div>\n

How Do We Express Obligation?<\/h2>\n

We use different words to show how strong an obligation is, or where the rule comes from.<\/p>\n

    \n
  • Strong Obligation (Internal\/Speaker's Rule):<\/strong> \u6211\u4eec\u4f7f\u7528 must<\/span> when the speaker feels the obligation strongly or is giving a direct order. It often comes from an internal feeling or the speaker's authority.<\/li>\n<\/ul>\n

    \u4f8b\u5982\uff1a I must finish this report by Friday.<\/span> (The speaker feels it's important.)<\/p>\n

      \n
    • Strong Obligation (External Rule\/Necessity):<\/strong> \u6211\u4eec\u4f7f\u7528 have to<\/span> when the obligation comes from an external rule, law, or situation.<\/li>\n<\/ul>\n

      \u4f8b\u5982\uff1a We have to wear a uniform at school.<\/span> (It's a school rule.)<\/p>\n

        \n
      • Advice or Weaker Obligation:<\/strong> \u6211\u4eec\u4f7f\u7528 should<\/span> \u6216 ought to<\/span> for recommendations, advice, or when something is generally a good idea.<\/li>\n<\/ul>\n

        \u4f8b\u5982\uff1a You should study more for the exam.<\/span> (It's advice.)<\/p>\n

          \n
        • Expected Obligation (often unfulfilled):<\/strong> Be supposed to<\/span> indicates an expectation or a plan that might not happen.<\/li>\n<\/ul>\n

          \u4f8b\u5982\uff1a I was supposed to call him yesterday, but I forgot.<\/span><\/p>\n

            \n
          • No Obligation:<\/strong> \u6211\u4eec\u4f7f\u7528 don't have to<\/span>, don't need to<\/span>, \u6216 needn't<\/span> when something is not necessary.<\/li>\n<\/ul>\n

            \u4f8b\u5982\uff1a You don't have to come if you're busy.<\/span><\/p>\n

              \n
            • Strong External Obligation (making someone do something):<\/strong> We can use verbs like make<\/span> \u6216 force<\/span> to describe when someone else causes an obligation.<\/li>\n<\/ul>\n

              \u4f8b\u5982\uff1a My boss made me work late.<\/span><\/p>\n

              How Do We Express Permission?<\/h2>\n

              When we talk about permission, we are saying that something is allowed.<\/p>\n

                \n
              • Giving or Asking for Permission:<\/strong> \u6211\u4eec\u4f7f\u7528 can<\/span> for general permission. May<\/span> is more formal.<\/li>\n<\/ul>\n

                \u4f8b\u5982\uff1a Can I use your pen?<\/span> (Asking for permission)<\/p>\n

                \u4f8b\u5982\uff1a You can leave early today.<\/span> (Giving permission)<\/p>\n

                  \n
                • Having Permission:<\/strong> \u6211\u4eec\u4f7f\u7528 be allowed to<\/span> \u6216 can<\/span> to state that permission exists.<\/li>\n<\/ul>\n

                  \u4f8b\u5982\uff1a Students are allowed to use their phones during the break.<\/span><\/p>\n

                    \n
                  • No Permission \/ Prohibition:<\/strong> \u6211\u4eec\u4f7f\u7528 mustn't<\/span> \u6216 can't<\/span> to say something is not allowed or is prohibited. Mustn't<\/span> is stronger and often implies a rule or danger.<\/li>\n<\/ul>\n

                    \u4f8b\u5982\uff1a You mustn't smoke in here.<\/span> (It's against the rules.)<\/p>\n

                    \u4f8b\u5982\uff1a You can't park here.<\/span> (It's not permitted.)<\/p>\n

                      \n
                    • Allowing someone to do something:<\/strong> \u6211\u4eec\u4f7f\u7528\u52a8\u8bcd let<\/span> to give permission for someone to do something.<\/li>\n<\/ul>\n

                      \u4f8b\u5982\uff1a My parents let me stay out late.<\/span><\/p>\n

                      Past Forms of Obligation and Permission<\/h2>\n

                      We can also talk about past obligations and permissions.<\/p>\n

                        \n
                      • Past Obligation:<\/strong> \u6211\u4eec\u4f7f\u7528 had to<\/span> for past necessities or rules.<\/li>\n<\/ul>\n

                        \u4f8b\u5982\uff1a Yesterday, I had to work until midnight.<\/span><\/p>\n

                          \n
                        • Past Expected Obligation:<\/strong> Was\/were supposed to<\/span> indicates an expectation in the past that might not have happened.<\/li>\n<\/ul>\n

                          \u4f8b\u5982\uff1a They were supposed to arrive an hour ago.<\/span><\/p>\n

                            \n
                          • Past Permission:<\/strong> \u6211\u4eec\u4f7f\u7528 could<\/span> \u6216 was\/were allowed to<\/span>. Could<\/span> is for general past permission, while was\/were allowed to<\/span> is for specific instances.<\/li>\n<\/ul>\n

                            \u4f8b\u5982\uff1a When I was a child, I could play outside until dark.<\/span> (General)<\/p>\n

                            \u4f8b\u5982\uff1a Yesterday, I was allowed to leave work early.<\/span> (Specific)<\/p>\n

                              \n
                            • Past No Permission \/ Prohibition:<\/strong> \u6211\u4eec\u4f7f\u7528 couldn't<\/span> \u6216 wasn't\/weren't allowed to<\/span>.<\/li>\n<\/ul>\n

                              \u4f8b\u5982\uff1a We couldn't use our phones during the exam.<\/span><\/p>\n\n\n\n\n\n\n\n\n\n
                              Summary of Obligation and Permission Expressions (B2)<\/caption>\n
                              \u529f\u80fd<\/th>\nPresent<\/th>\nPast<\/th>\nNegative \/ No Obligation<\/th>\n<\/tr>\n<\/thead>\n
                              Strong Obligation (Internal)<\/span><\/td>\nmust<\/span><\/td>\nN\/A (use had to<\/span>)<\/td>\nmustn't<\/span> (prohibition)<\/td>\n<\/tr>\n
                              Strong Obligation (External)<\/span><\/td>\nhave to<\/span> \/ need to<\/span><\/td>\nhad to<\/span> \/ needed to<\/span><\/td>\ndon't have to<\/span> \/ don't need to<\/span> \/ needn't<\/span><\/td>\n<\/tr>\n
                              Advice \/ Weaker Obligation<\/span><\/td>\nshould<\/span> \/ ought to<\/span><\/td>\nshould have + PP<\/span><\/td>\nshouldn't<\/span><\/td>\n<\/tr>\n
                              Expected Obligation<\/span><\/td>\nbe supposed to<\/span><\/td>\nwas\/were supposed to<\/span><\/td>\nnot supposed to<\/span><\/td>\n<\/tr>\n
                              Permission<\/span><\/td>\ncan<\/span> \/ may<\/span> \/ be allowed to<\/span> \/ let<\/span><\/td>\ncould<\/span> \/ was\/were allowed to<\/span> \/ let<\/span><\/td>\ncan't<\/span> \/ may not<\/span> \/ not allowed to<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                              \u793a\u4f8b<\/h2>\n
                                \n
                              • You must submit your assignment by Friday.<\/span><\/li>\n
                              • I have to attend a meeting tomorrow morning.<\/span><\/li>\n
                              • You should apologize for your mistake.<\/span><\/li>\n
                              • We are supposed to meet at 7 PM.<\/span><\/li>\n
                              • You don't have to pay for the tickets; they're free.<\/span><\/li>\n
                              • Can I borrow your laptop for a moment?<\/span><\/li>\n
                              • Students are not allowed to eat in the library.<\/span><\/li>\n
                              • My parents let me travel alone when I was 16.<\/span><\/li>\n
                              • He was forced to resign from his position.<\/span><\/li>\n
                              • When I was younger, I could stay up late on weekends.<\/span><\/li>\n<\/ul>\n

                                \u7ec3\u4e60<\/h2>\n