Modal (auxiliaries) | Must, shall, and, should

Hello there! Building on our previous discussions about modal verbs, let’s explore three more crucial ones: Must, Shall, and Should.

As we’ve established, modal verbs (also known as modal auxiliaries) are special types of auxiliary verbs [Previous Conversation, 489, 500, 506, 696]. A key characteristic is that they are non-tensed auxiliaries [Previous Conversation, 498, 500, 506, 696]. This means they do not inherently indicate tense on their own, nor do they take inflections like ‘-ing’, ‘-es’, or ‘-ed’ [Previous Conversation, 695, 696, 698, 699]. They are used to express various modalities such as likelihood, ability, request, capacity, suggestion, obligation, or advice [Previous Conversation, 481, 489, 677, 698]. It’s also important to remember that modal auxiliaries like ‘could’, ‘might’, ‘should’, and ‘would’ are independent modal auxiliaries and are not simply the past forms of ‘can’, ‘may’, ‘shall’, or ‘will’.

Let’s break down ‘Must’, ‘Shall’, and ‘Should’ with ease!

1. Must 🌟

The core meaning of ‘must’ is necessity.

• Necessity (based on the speaker’s knowledge or deduction) 🧠

  • It indicates a strong deduction or certainty about something.
  • Example: “Look at how thick that canopy is. Trees must have many branches.” (Deduction based on observation)
  • Example: “Fan is not working. It must be power failure.” (Deduction)

• Obligation (varying in strength) 🤝

  • Self-imposed obligation (weak form, often with first-person pronouns, like a reminder to oneself).
    • Example: “I must visit him today.”
    • Example: “I must clean the room now.”
  • Non-personal obligation (involves human performers but is not a direct personal imposition).
    • Example: “Submissions must follow the guidelines as instructed by the scientific committee.”
  • Social obligation (vague in terms of actual occurrence, but socially expected).
    • Example: “We are going to Bangalore tomorrow. We must visit Ramesh’s uncle and his family.”

• Negative Counterpart: Must not (Mustn’t) 🚫

  • Indicates necessity in obligations and is often more forceful. It implies something is forbidden or highly discouraged [31C].
  • Example: “You must not be distracted while driving.”
  • Example: “You must not use your phones while at fuel station.”

2. Shall 🚀

‘Shall’ is primarily used to indicate an element of determination on the part of the speaker. It can also show intention, willingness, and prediction when used as a modal auxiliary.

• Determination / Intention / Willingness / Prediction 💪

  • Often used with first-person pronouns (I/we) in contemporary English to show a strong resolve or plan.
  • Example: “I shall talk to you about the proposal tomorrow.” (Shows intention/determination)
  • Example: “We shall have finished the work by noon.”

• Strong Obligation (often socially oriented, particularly in legal or formal contexts) 📜

  • This usage implies a very firm rule or command, typically found in official language.
  • Example: “The doctors who do not abide by the guidelines of IMA for practicing medicine shall have their licenses revoked with immediate effect.”
  • Example: “The petitioners shall present the affidavit in regard to the issues submitted to the court.”

• Note on ‘Will’ Interchangeability: While ‘shall’ can sometimes be used interchangeably with ‘will’ as a tense auxiliary (e.g., in expressing future tense), when ‘shall’ functions as a modal auxiliary, it is not considered a substitute for ‘will’. It carries a stronger sense of determination or obligation.

3. Should ✅

The core meaning of ‘should’ is requirement. It is commonly used in socially rooted contexts to indicate weak obligations, advice, or suggestions.

• Requirement / Advice / Suggestion 👍

  • Indicates what is considered appropriate behaviour or a good idea. It’s less forceful than ‘must’ [32E].
  • Example: “You should prepare well for the learner’s test.” (Advice/Requirement)
  • Example: “You should inform me before you leave.” (Requirement/Weak obligation)
  • Example: “It’s a good film. You should go and see it.” [32B]
  • Alternative: ‘Ought to’ can be used as another way to say ‘should’ [32F].

• Strong Denial (when used with ‘why’ questions) 🤷‍♀️

  • This construction often functions as a rhetorical question, denying the relevance or possibility of an action.
  • Example: “Why should I see the movie? I don’t.” (Strong denial of watching the movie)
  • Example: “Why should we do what everyone else does?” (Denial)

• Probability 🎲

  • Can indicate what is most probable or expected to happen.
  • Example: “This work should take two or three days.” (Indicates probability)
  • Example: “Your order should be delivered in six to seven days.” (Indicates probability)

Key Distinctions Summary 🔑

• Must: Strongest for necessity or strong obligation (especially prohibitions with ‘must not’).
• Shall: Formal, often indicates speaker’s determination or strong, often legal, obligation.
• Should: Weaker, for advice, suggestions, weak obligations, or what is generally required/expected.

Practice Questions 📝

Choose the most appropriate modal verb (‘must’, ‘shall’, or ‘should’) for each sentence.

1. Drivers _______ follow the speed limits. 🚗
2. You look tired. You _______ get some rest. 😴
3. I _______ be there to support you, no matter what happens. 💪
4. Why _______ I apologize? I haven’t done anything wrong. 😡
5. All employees _______ wear their ID badges at all times. 🪪
6. The package _______ arrive by Friday, but it’s not guaranteed. 📦
7. We _______ definitely try that new restaurant; I’ve heard great things! 😋

Solutions ✅

1. Drivers must follow the speed limits. 🚗 (Strong obligation/rule)
2. You look tired. You should get some rest. 😴 (Advice/Suggestion)
3. I shall be there to support you, no matter what happens. 💪 (Speaker’s determination/strong intention)
4. Why should I apologize? I haven’t done anything wrong. 😡 (Strong denial/questioning relevance)
5. All employees must wear their ID badges at all times. 🪪 (Non-personal/formal obligation, a rule)
6. The package should arrive by Friday, but it’s not guaranteed. 📦 (Probability/expectation, not certainty)
7. We should definitely try that new restaurant; I’ve heard great things! 😋 (Suggestion)