The main verb can never be the to-infinitive. We cannot say: He should to go. There is no short form for should, but we can shorten the negative should not to shouldn't. 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. The content systematically explores should as a fundamental modal auxiliary verb that serves three primary functions: expressing advice and recommendations, indicating mild obligation or responsibility, and conveying expectations about future events or logical deductions. SHOULD definition: must; ought (used to indicate duty, propriety, or expediency). See examples of should used in a sentence. The meaning of SHOULD is —used in auxiliary function to express condition —usually used with if. How to use should 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. Learn how to use SHOULD or SHOULDN'T to give advice, suggestions, opinions and recommendations in English. Should is a modal verb, and modal verbs are followed by an infinitive (without to). 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. Sometimes Should is used instead of Must to make rules, orders or instructions sound more polite. This may appear more frequently on formal notices or on information sheets. Learn the difference between must vs should with clear examples to improve your English grammar, writing, and speaking.