Practice
Must or should: choose rules and advice
Sign in to saveThe museum says visitors must leave large bags at reception. Your friend says you should take a jacket because the building is cold. Both words matter, but they give different strength to the message.
Choose must or should by deciding whether a sentence gives a strong rule, a necessity, advice, or a recommendation.
Read and practice
Read the examples and try the written questions in this guide. Listening recordings are not available for this lesson yet.
Try the written questions
Must I bring my passport, or should I wait? /mʌst aɪ brɪŋ maɪ ˈpɑːspɔːt ɔː ʃʊd aɪ weɪt/
The short answer
Use must when something is required or necessary. Use should when you are giving advice or saying what is a good idea.
You must show your ticket at the entrance.
Why it works: Showing the ticket is a requirement, so must is stronger than should.
5 more examples
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All visitors must wear a badge in this building.
The building has a rule, so must shows that the badge is required.
Not this:You
should weara badge if you want staff to recognize you quickly. What changes: This is practical advice, not a stated rule. -
You should save a copy before you close the form.
Saving a copy is a sensible recommendation.
Not this:You
must savethe form before the system will accept it. What changes: The system requires the action, so must is appropriate. -
Passengers must not open the emergency door.
Must not gives a strong instruction that forbids the action.
Not this:Passengers
do not have to usethe side door. What changes: The side door is optional. The sentence does not forbid it. -
You should call Maya before the meeting.
The speaker thinks that calling Maya is a good idea.
Not this:You
must callMaya before the meeting because she has the access code. What changes: The call is necessary for the meeting plan. -
Should we book the tickets today?
Should can ask for advice about the best action.
Not this:
Must we bookthe tickets today? What changes: Must asks whether the booking is a requirement.
Read the full guide
Read the reason for the sentence before you choose a modal verb. Must tells someone about a requirement or a strong need. Should gives guidance while leaving the person a choice. Then check the form after the modal: use the base verb, such as must leave or should call.
Use must for rules and strong necessity
Must shows that an action is required or necessary. A notice, an instruction, or a speaker can give this strong message. Use it when the listener needs to understand that the action is not simply a suggestion.
Employees must wear closed shoes in the workshop.
The workshop rule requires the shoes, so must fits the sentence.
I must finish this application before midnight.
The speaker sees finishing the application as necessary.
Which modal fits a sign that gives a safety rule?
Use must when the sign tells people what they are required to do.
Use should for advice
Should gives advice about a good or sensible action. The speaker recommends the action, but should does not usually create a rule. It is useful when you want to help someone decide what to do.
You should check the address before you send the parcel.
Checking the address is good advice before sending the parcel.
We should leave early to avoid the traffic.
Leaving early is a recommendation for an easier journey.
Which modal fits friendly advice from a colleague?
Use should when the colleague recommends an action.
Keep must not separate from optional actions
Must not means that an action is prohibited. It is much stronger than advice. Do not use must not to say that something is unnecessary. Say do not have to when a person can choose whether to do something.
You must not take photos in this room.
Taking photos is forbidden in this room.
You do not have to print the receipt.
Printing is optional, so the sentence does not ban it.
Which phrase tells someone that an action is optional?
Use do not have to when the action is not required.
Use the base verb after each modal
Must and should are followed by the base form of the verb. Do not add to after either modal. This pattern stays the same with different subjects: I should go, she should go, and they should go.
You must arrive by nine o'clock.
Arrive is the base verb after must.
He should ask for help.
Ask is the base verb after should.
Which form completes the sentence: You should ___ the instructions?
Use read: You should read the instructions.
Ask whether it is required or recommended
Questions with must ask about a requirement. Questions with should ask for advice. Look at the reason for the question before you answer it. The modal shows what kind of answer the speaker needs.
Must I sign this form today?
The speaker asks whether signing today is required.
Should I sign this form today?
The speaker asks for advice about the best time to sign.
Which modal asks for advice about a decision?
Use should when you want advice about what to do.
Before you go
Remember this
Choose must for a rule, a requirement, or a strong need. Choose should for advice about a good action. Put the base verb after either modal. Remember that must not forbids an action, while do not have to says the action is not required.
Practice with the written examples
You can practice with the written questions in the Learn tab. Each answer includes an explanation.
Try the written questionsListening test not available yet
This lesson does not have the recordings needed for a listening test. Use the written questions in the guide to check your understanding.
Try the written questionsQuestions about "Must or should: choose rules and advice"
What is the difference between must and should?
Must gives a strong message about a rule, a requirement, or something necessary. Should gives advice about a good or sensible action. Choose the modal by asking whether the speaker requires the action or recommends it.
All visitors must wear a badge in this building.
Can must and should both be used for advice?
Should is the usual choice for ordinary advice. Must can express a speaker's very strong view that an action is necessary, so it sounds stronger. Use the situation to decide whether the listener has a real choice.
You should wear a badge if you want staff to recognize you quickly.
What is the difference between must not and do not have to?
Must not means that an action is forbidden. Do not have to means that an action is optional or unnecessary. The difference matters because must not tells someone not to do the action, while do not have to leaves the choice open.
You should save a copy before you close the form.
What verb form comes after must and should?
Use the base form of the verb after both modals: must leave, should leave, must be, and should be. Do not add to after must or should. The form does not change with the subject.
You must save the form before the system will accept it.
How do I use must and should in questions?
Use must in a question when you want to know whether something is required. Use should when you want advice about a decision. Put the modal before the subject, then use the base form of the verb.
Passengers must not open the emergency door.