Should vs. Be Supposed To vs. Have To vs. Must | Talking about Obligation

What might be the difference among these sentences?

We must wait for our boss before we open.

We have to wait for our boss before we open.

We are supposed to wait for our boss before we open and we should wait.

In each example we're using a modal of obligation.

This is a verb that expresses necessity advice or a rule that cannot

be broken,

but each modal highlighted here communicates a different level of

expectation from personal advice to strict rules.

So how do you know when to use should be supposed to

have to and must. In this lesson,

we'll break down the subtle but important differences.

Explore real life examples and learn how to avoid common mistakes.

Plus you'll have the chance to practice with some bonus questions to make sure

you've got it right.

However, before we go any further, if this is your first time here, welcome.

I am Annemarie, an English confidence and fluency coach.

Everything I do is designed to help you get the confidence you want for your

life and your work in English.

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you can get all of that at my Speak Confident English website.

And now let's get right into the first of our four modal verbs of obligation.

Should English speakers use this modal for mild obligation

or to provide advice, for example,

you should start setting aside money for a rainy day fund.

That sentence isn't a strict rule that you absolutely have to follow.

It is simply some advice that I'm offering to you. Here's another example.

You shouldn't smoke so much. It's bad for your health.

We often use this negative form.

Shouldn't to say that something is either a bad idea or not really

socially accepted. With this in mind, let's move on to be supposed to,

which is also used for mild obligation. However,

the perspective is different.

If should is used to suggest what I think is important,

my advice for you to be supposed to is used to suggest what

is socially expected. In other words,

it's what others think is right or a large group of people think is

right. This structure is very often used to describe social norms,

expectations, and unsaid rules. For example,

he was supposed to call me. It's an expectation. You're supposed to say,

I'm sorry when you hurt someone's feelings.

This is a social norm and an unspoken rule.

We are supposed to arrive by 10:00 AM a social expectation.

So let's do a quick comparison. I've got two sentences here.

Rosie should be here by 9:30 AM.

Rosie is supposed to be here by 9:30 AM.

The first indicates that it's something I expect,

and the second indicates that it's something that is expected by a larger group

of people, perhaps by the whole office.

In addition to indicating those social obligations or social norms to

be supposed to can also mean that something is likely to happen.

Someone is reputed to do something or that the opposite

was expected to happen.

Take a look at these three sentences to see that in action.

The train is supposed to arrive at 11:30 AM This is focused on

likelihood. Micah is supposed to be the best pottery studio in town.

This is about reputation and lastly, it was supposed to rain today,

but the sky looks clear.

This is about unmet expectations or when the opposite occurs.

With that clarity of should and be supposed to,

let's move on to the next level of obligation using Haveto.

We use have to to express much stronger obligations usually as

a result of external forces, like general rules.

We can also use have to for personal commitments such as a

promise that you've made to somebody. For example, when they reach this age,

children have to go to school.

I have to brush my teeth two to three times a day.

I have to remember to buy bread on the way home.

Do I have to wear a tuxedo for this event?

And you don't have to work during the holiday season.

Each one of these example sentences highlights a stronger obligation due to

some rule that's in place or a personal commitment.

Now I want to pause and focus on that last example using the negative form.

You don't have to work when we use have to in the

negative form. It means that something is not necessary. It's not expected,

but you certainly could do it if you want to.

There's nothing preventing you from doing it. For example,

I don't have to wake up early on the weekends. I can if I want to,

but it's not necessary. It's not expected.

Before we move on to talk about must, I want to do another comparison.

I'm supposed to be at the airport by 6:00 PM I have to be

at the airport by 6:00 PM In that first example with be supposed to

it's mild obligation. It's not a strict rule,

and as a result it suggests that maybe someone else expects me

to arrive at that time, but there's room. I don't need to rush.

If I'm running late, it's no big deal.

The second example implies that there's a strict rule in place.

If I'm not there at 6:00 PM I'm most likely going to miss my flight.

So there's a different sense of urgency and need in that second

example with have to now let's talk about must for stronger

obligations and requirements. This word,

when talking about obligations can also refer to moral obligations,

the law, or strongly held opinions. For example,

applicants must provide a copy of their immigration

documents. This isn't just something they should do,

it's not a mild expectation. It's the rule or it's the law.

Similarly, you mustn't drive under the influence of alcohol.

Once again, this is a law.

Let's talk a little bit further about using this in the negative form.

When we highlighted using have to in the negative,

we said that it was not necessary to do something,

but it is okay if you want to. Nothing is prohibiting you.

That isn't true with mut. When we use it in a negative form,

it means that something is prohibited or forbidden. For example,

employees mustn't share company accounts. This is forbidden by the company.

Let's take a look at a few more example sentences.

Using must to also illustrate its use with strongly held personal

opinions, insistence and moral obligation.

You must come to our house for dinner on Friday night.

This is a personal insistence showing how strongly I

want that to happen or how strongly I believe that it should happen.

You must address those concerns with your boss before it's too late.

The kids must study hard to pass their exams.

Now that we have this clear understanding of the differences in

meaning between should be supposed to have to and must.

I also wanna talk about grammatical function when it relates to past and future

obligations.

When we talk about strong obligations that we had in the past,

we use had to or didn't have to,

we cannot use must to talk about those past obligations.

For example, when I was young,

we had to wear uniforms at school. It's a past obligation,

so I'm using had to.

It doesn't work to use must in the past.

Here's another example. When I applied,

I didn't have to submit additional documents. Again,

I'm talking about a past obligation.

So using that negative form with the past tense. Now,

when we shift to future focus,

we could use must or will have to. For example,

we will have to or we must apply for an evis when we buy

our plane tickets.

Both of those are perfectly correct for a future obligation.

I've got a bonus practice for you.

But first I wanna do a quick recap of what we've learned.

Should is used for advice, suggestions,

and mild obligations be supposed to is also used for mild

obligations. However, from a different perspective,

from social expectations and norms. When we get to have to,

we've transitioned into stronger obligations of personal commitments

and rules. And finally,

must is our strongest of all focused on moral obligations,

laws, and authority.

And here are four sentences to help illustrate each one of those.

You should eat more vegetables. You're supposed to wear a tie to the wedding.

I have to finish this report by tomorrow. You must report crimes to the police.

I have four sentence starters for you. With each one,

there's an empty space for you to select the modal of obligation that you think

fits best. And then I want you to continue that sentence.

I want you to complete it. You can do it in a few ways. Number one,

you can do it in a notebook at home where you practice English.

You can share with me here in the comments.

You can also visit this lesson over at my Speak Confident English website and

leave a comment there as well.

In addition to sharing these sentences here on screen,

I'll share them in the notes below so that you can see them.

Take a moment to review and practice what you've learned.

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