We use the full form should not in formal contexts or when we want to emphasis something: We should not forget those who have given their lives in the defence of freedom. This article explains the use of should in sentences in English grammar. It also describes the use of should, use of shall, and would and use of ‘should have’. SHOULD definition: must; ought (used to indicate duty, propriety, or expediency). See examples of should used in a sentence. Learn how to use the English verbs should, must, and ought to. Get clear, simple grammar advice from expert English teachers at the British Council. should (third-person singular simple present should, no present participle, no simple past or past participle) (modal, auxiliary, defective) Ought to; indicating opinion, advice, or instruction, about what is required or desirable. SHOULD definition: 1. used to say or ask what is the correct or best thing to do: 2. used to show when something is…. Learn more. Should is a modal verb, and all modal verbs are followed by an infinitive (without to). You should to listen to me. You should listen to me. The negative form of should is should not or shouldn’t. You should not be here. = You shouldn’t be here. To ask questions, we use should + subject + infinitive. We don’t use the verb do to ask questions. Usage: Should has, as its most common meaning in modern English, the sense ought as in I should go to the graduation, but I don't see how I can. However, the older sense of the subjunctive of shall is often used with I or we to indicate a more polite form than would: I should like to go, but I can't. The meaning of SHOULD is —used in auxiliary function to express condition —usually used with if. How to use should in a sentence. The simple definition of SHOULD is —used to say or suggest that something is the proper, reasonable, or best thing to do.