Modal verbs in English grammar express the ability, permission, obligation, possibility, etc. Modal verbs only have one form, meaning that they are used in simple present and don’t have past simple and past participle forms. The negative form of 'should' is 'should not' or 'shouldn't', and it is used to express prohibition, absence of obligation, or to give emphasis in formal contexts.
However, some modal verbs can have alternative forms which can be used in different tenses.
Giving Advice
Rule 1: We can use should to give advice and make suggestions to do something or express that something is a good idea. When giving advice, it is important to consider the context and the needs of the person.
Rule 2: We can use shouldn’t, which is the contraction of should + not, to give advice and make suggestions not to do something or express that something is not a good idea.
Rule 3: We can use should + have + past participle to make suggestions about something that has already happened in the past. Here are some examples to illustrate this usage.
Modal Verbs for Obligation
Rule 4: We can use should in the meaning of be supposed to or be expected to to give orders or advice but not in a strong way. In such sentences, the subject typically follows the modal verb 'should'.
Note: We can use ought to/ought not to instead of should/shouldn’t. There is no difference between them, although ought to is less common and more formal than should
Quiz
1/4Choose the correct modal verb: You ___ turn off notifications when you're at the cinema.