41 Should: Modal Auxiliary Verb


A modal verb is a type of auxiliary (helping) verb that has no meaning on its own but it modifies the main verb, changes his meaning and gives more details about the action.

Should is a type of auxiliary modal verb used to express obligation and duty through advice or recommendations.


Should always has the same form even for the third person, and we find this structure in its three forms.


Its structure, in the affirmative form, is:
Subject + should + verb + …

Subject should Verb
I/You should work
He/She/It should work
We/You/They should work


Its structure, in the negative form, is:
Subject + should + not + verb + …

  • Short version of the negative form is: shouldn’t.
Subject should + not Verb
I/You should not work
He/She/It should not work
We/You/They should not work


Its structure, in the interrogative form, is:
Should + subject + verb + …?

Should Subject Verb Question
Should I/you work ?
Should he/she/it work ?
Should we/you/they work ?


  1. Weaker obligation/duty
    • should never be late to school again!
    • He shouldn’t talk to his classmates during the exam.
    • We should always wear a seat belts whilst driving a car.
  2. Advice (recommendation)
    • You should be quiet when you visit a public library.
    • She shouldn’t revise the parts that are not to be examined.
    • Should we memorise this rule?


Should can be considered not to be as strong as must. We use should when:

  1. We indicate weaker obligation or duty;
  2. We give and ask for advice (recommendation).


The modal verb should expresses weaker obligation or advice. It can be considered not to be as strong as must.

The structures are:

  • Affirmative: Subject + should + verb + …
  • Negative: Subject + should + not + verb + …
  • Interrogative: Should + subject + verb + …?

For example:
— Affirmative: “You should do your homework to understand the subject.” = Should is used to give advice in a friendly manner.
— Negative: “You shouldn´t do your homework to understand the subject.” = Shouldn’t is used to give advice in a friendly manner.
— Interrogative: “Should you do your homework to understand the subject?” = Should? is used to ask for a confirmation of advice.
♦ “You must do your homework or you will fail the class.” = Must expresses stronger obligation.

Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.

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