Understanding the Usage of Should, Ought to, and Must with Verbs

In the English language, modal verbs such as should, ought to, and must play a crucial role in expressing modalities and obligations. These verbs are used to prescribe, recommend, or mandate actions and to convey a sense of necessity, certainty, or advice.

Introduction to Modal Verbs

Modal verbs are auxiliary verbs that express modality or the degree of likelihood, possibility, necessity, or obligation. Besides should, ought to, and must, other modal verbs include can, will, may, and might. Notably, all modal verbs are followed by the base form of the verb, never a past, participle, infinitive, or -ing form.

The Rule for Using Should, Ought to, and Must with Verbs

The key rule to remember when using should, ought to, and must with verbs is that the verbs take their base form regardless of the tense. For example, must go (simple present), should have gone (past perfect), and ought to be going (present continuous). These modal verbs are part of a category known as the subjunctive mood, which expresses actions and states that are not factually true, such as wishes, hopes, or desires.

Subjunctive Mood and Action

Subjunctive statements are never based on factual reality but on imagined outcomes or states. For instance, when you say, "It goes to class, present tense," or "She had gone to work, past tense," these are factual statements. However, in the subjunctive mood, you would say, "He ought to be going to class, present continuous subjunctive," implying a state that is not necessarily true or actual at the moment of speaking.

Contextual Usage of Should, Ought to, and Must

Should and ought to are often used interchangeably to express recommendations, advice, or subtle obligations. While they are quite similar, ought to is generally more formal and less casual.

Example: You ought to respect elderly people. You ought to eat more vegetables.

Note, however, that ought to is rarely used in spoken English, making it more common in formal or written contexts.

Usage with Must: Must is used to express a stronger obligation or necessity. It can also be employed to express certainty. When you feel a deep sense of inner obligation, use must. For example, "I must study hard at university because my parents have worked a lot to afford this expense," indicates a strong sense of duty.

Examples of Using Must

Expressing obligation: You must not smoke in hospitals. You are not allowed to. Expressing certainty: He must be in the house because the lights are on. Expressing deduction: They must have left. No one answers the phone.

Concluding Thoughts

Understanding the proper usage of should, ought to, and must with verbs is crucial for effective communication. Whether you are writing formally, giving advice, or expressing a strong obligation, these modal verbs significantly influence the tone and meaning of your sentences.

By mastering the nuances of these modal verbs, you can convey a more refined and precise message in your writing or speech.