Necessity and Obligation

Necessity is a noun. It refers to something that we have to do.

Obligation is also a noun. It refers to something that we are obliged to do.

Obligation and Necessity

An obligation is something you have to do, generally because of a social situation.

Children are obliged to attend school between the ages of five and fifteen.

A necessity can refer to something that you have to do for a physical reason.

Eating and drinking are necessities of life.

The Work Page

On the work page, the title is “Things you have to do”.

Link to the Work Page

Do you have to work?

Some people don’t have to work.

First Conditional

If you are wealthy or retired, you don’t have to work.

Things that you Love Doing

Is work a necessity or an act of love?

Some people love their job.

Are you one of those people who loves their job?

Working for Love

In life we usually have to spend a lot of time working, so you are lucky if you have found a job that you love.

Have you found a job that you love?

Work brings us money but it also gives us contact with other people and it gives us a sense of meaning if we have a meaningful job.

Meaningful Jobs and Meaningless Tasks

Tell us about your job. Is it meaningful or is it just drudgery?

Modals Verbs of Necessity and Obligation

Modal verbs don’t take “to” with an infinitive:

I want to work


I must work.

Strictly speaking, “have to” is not a modal verb because it has to but we usually study “must” and “have to” together because their meanings are very similar.


These two phraes are the same:

You have to go to school.
You must go to school.

Negative Forms

Theses two forms are quite different:

You don’t have to wear a uniform.

You must not smoke.

The first one (don’t have to) means it is not necessary to wear a uniform.

The second one (must not) means it is necessary not to smoke.

The Vocabulary of Obligation

An obligation is something that you have to do. There are several ways to express obligation.

Informal Conversation

I have to go to the toilet.
I must go to the toilet.
I need to go to the toilet.

Military Service

In some countries military service is compulsory. That means you have to do military service.

Adjectives of Obligation

Look at these adjectives:

Military service is compulsory.
Military service is mandatory.
Military service is obligatory.

Compulsory Schooling

Education is also compulsory in most countries. That means you have to attend school between the ages of 5 and fifteen. Each country is different.

What are the ages for compulsory education in your society?

Questions about Women and Education

Are women required to go to school.
Are women obliged to go to school?
Is it compulsory for women to go to school?

The above three sentences have the same meaning but the first two are formed as passive verbs. You can analyse them in two ways. They could be seen as as passive sentences or you could see them as a “be” verb plus adjective combination.

The third adjective (compulsory) is different. It is a normal adjective so there is just one way to analyse it. Look at the word family.

Word Family

compulsory (adjective)
compulsive (adjective)
compulsion (noun)
compel (verb)

Note that there are two adjectives. Compulsory education is obligatory schooling for children of certain ages.

Obsessive Compulsive Disorder

Obsessive compulsive disorder is a medical condition where the sufferer feels compelled (or forced) to engage in some kind of activity. The activity might be a twitch of the neck or a flick of the hand but it might also be something more complex like washing feet or adding too much salt to food.

Questions about OCD

Do you suffer from OCD?
Do you know somebody who does?

The Verb “compel”

He compelled his troops to attack the hill.
He forced his troops to attack the hill.

The Adjective – compelling

A compelling story is a story which absorbs you and engages you and you don’t want to stop listening (or reading) until it is finished.

Word Families

Let’s look at the word families oif these three words:


Word Family – Necessary

It is necessary to eat healthy food and drink enough water.
You have to eat healthy food and drink enough.

Generalisations are not necessarily true.
General statements are not categorically true.

The problem of climate change necessitates action.
We have to do something about climate change quickly.

The necessaries of life have become more expensive.
Food has become more expensive.

Word Family – Oblige

I am much obliged.
I am very grateful.

I have family obligations which means I cannot mean you on the week-end.
I have things that I have to do for my family so we can’t meet.

Word Family – Require





Abilities and Possibilities

Link to the Work Page

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