Modal Auxiliary Verbs

                                       

In English there are certain auxiliary verbs which always accompany a main verb introducing a modality of ability, permission, probability or future, suggestion or advice and obligation in the meaning of the sentence. They are different from the main auxiliary main verbs Be, Have and Do because these three verbs can function alone in the sentence as main verb with meaning (“ser / estar, tener, hacer” correspondingly) or they can accompany a main verb in order to form another tense. For example:

Be: the Continuous tense (Present, Past and Future Continuous) and the Passive Voice.

Have: the Perfect (Present, Past and Future Perfect), similar with Spanish “haber”.

Do: forms the negative and interrogative sentences in the Present/ Past Simple tenses.

The modal auxiliary verbs are immediately followed by the main verb or the particle “not” and the main verb without “to” and modals never have suffixes of the Past tenses or the third person singular of the Present Simple tenses.

 

Then we have the following modal auxiliary verbs in the Present form:

-Can: it means ability and possibility. Also in the interrogative form can mean permission.

Examples: She can swim quite well.     They can arrive earlier than expected.  

We can not (can´t) speak Russian.   Can we enter into the mosque?

-Could: it is the past form of the can and it means ability in the past or conditional and an hypothetical possibility or dependent on a conditional.

 

-May: it means probability and permission in the interrogative form

It has not got contraction just “may not” and in this meaning it can be interchangeable with “can” in many sentences.

Examples: It may rain today.  They may not come to the party. May I help you, Sir?

-Might: it means hypothetical probability, it can have contraction “mightn´t”.

Examples: She mightn´t finish the task at home.  Might it run at the race?

 

-Will: it conveys future and it is used in spontaneous decisions, promises, predictions.

Examples: They will study Chemistry next term. I will answer the emails immediately.

Will you help me in the office?  We will donate to the victims of the volcano eruption.

They will not/won´t come back to our town in my lifetime. She will fall in love with me

-Would: it is used in 2nd and 3rd conditionals and it is used in all the uses of “will” though with a more hypothetical or polite meaning.

 

-Shall: in the affirmative form means probability or future, promise or suggestion and obligation or condition because it is used as a subjunctive in formal sentences. It is hardly used in American English where should is used instead.

Example: You shall not murder. We shall work in the pub next week. Shall he come in?

I shall get off the train in three hours. We shall help you then. You shan´t open the door.

-Should: it is the past form of shall and it is more used today than “shall” and it means probability, suggestion, advice or obligation and opinion.

Examples: It should be cold in winter. You should phone them in case of an accident.

My sister should have told us immediately. Should I use make up at work?

 -Must: it is the most important obligation of all modal verbs and the speaker considers it usually necessary.

In the negative form it expresses prohibition or it is used to forbid something.

Examples: You must leave early to catch the train on time. I must study harder to pass.

You must not/ mustn´t use your mobile phones at class.   He must arrive before dawn.

We must hand out the keys to get back the deposit.  They mustn´t smoke in the kitchen.

-Ought to: it is a semi modal and it means obligation and prohibition though it can convey advice or making a logical opinion, sometimes it is considered as the past, conditional or hypothetical form of must and it usually replaces “should” too.

Examples: You ought to clean the rooms before your departure.

They oughtn´t leave garbage behind in case the landlord complains.

You ought to lose weight to be healthier.  She ought to work hard to gain their respect.

 

-Have to: it is a semi-modal or periphrastic modal. It means an impersonal obligation usually to comply with an order, and its verb is the main verb in the sentence.

Examples: In UK drivers have to drive on the left. Do you have to wear an uniform?

We don´t have to switch off our mobiles phones during the match in the stadium.

In China citizens have to comply with the rules of the Communist Party.

 -Need: it is a semi auxiliary verb because it can accompany a main verb or it can function alone in a sentence as a lexical or main verb (e.g. We need coffee) and in both situations means the necessity of the verb to do something. In the negative form it means “don´t have to”.

Examples: We need to convince her.   I need not tidy the dining room at the moment.

She needs to study harder.  They don´t need to pass the exam in order to work as clerks.

 

-Be able to: this is a semi modal auxiliary verb and it means the ability, probability or possibility to do something, especially in the past or passive forms and it changes its ending according with the necessary inflection with the subject in the sentence.

Examples: We were able to unlock the door. She was not able to run faster.

They will be able to work soon after the course is finished.  He is able to drive trucks.