Talking about necessities ,suggestions and expectations
When we talk about obbligation and necessity we use the modal verb Must.
If your teacher is giving you instructions or your mother is telling you what she wants you to do we use the verb Must:
“Remember you must study all the irregular verbs”
” Before you go out you must do your homework.”
Now watch the video where a teacher is explaining the meanings of some modal verbs:
The modal verb Should is usually used for asking for advice and giving advice. It is also used for talking about expectations.
When we give advice we can use also must , but we mean strong advice on behalf of the person who is speaking.
For example if you really like a film and you think a fried should see it you can give advice by saying
” You should see the film. It is one of the best films I have ever seen”
” You must see the film” , here the speaker is suggesting that it is really worth seeing this film ( strong advice)
Ought to is similar to should but it is more formal.
Talking about prohibitions : MUSTN’T
We use mustn’t/ must not when we say that you cannot do something, you are not allowed to do something.
It’s 2 o’clock now: you mustn’t go out with your friends. You must do your homework
You musn’t touch my mobile phone : it’s mine!!
When do we use ” HAVE TO”?
This verb is not a modal verb: we use it in the present, in the past and other tenses in which we cannot use the verb must meaning obbligation and necessity.
I live far from the city so I have to commute to work every day ( a habit and a necessity)
What time did you have to leave yesterday?
George had to go to work late yesterday ( an event in the past)
Jack will have to help me next week ( future event)
When we use ” have to ” in the present or in the past we must remember to use the auxiliaries do/does and did in questions and negative forms.
MUSN’T AND DON’T/DOESN’T HAVE TO
When we are talking in the present and we are focussing on what is required to do and what is not required to do or it is not necessary to do we must be careful when choosing the right form:
- When we do not want something to happen because it is bad for us or it is not possible to do it we use MUSN’T+ base form
“Kevin! You musn’t touch the wires- they are dangerous”
- When we talk about something that is not necessary to do but it could be done we use
don’t/doesn’t have to:
“Tomorrow I am not going to work so I don’t have to go to bed early tonight ” ( It is not necessary for me to go to bed early tonight)
The Verb NEED
This verb can be considered a sort of semi-modal verb:
Positive form : I need to leave early ( I have to leave early ),it is similar to the verb to have need is followed by to+infinitive
Interrogative form: Do you need to leave home early every day? ( we use the auxiliary do/does in the simple present)
Needn’t / don’t/doesn’t need to
In the present simple form need can be a modal verb or not : it is used to say that it is not necessary to do something.
“You needn’t go to school tomorrow ” ( it means that it is not necessary to go to school)
You could also say ” You don’t have to go to school tomorrow ”
LINKS ONLINE FOR GRAMMAR EXERCISES
http://baladre.info/english/sedaviwebfront/mustshould.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=3401
http://englishservice.cz/download/Must%20have%20to.pdf
http://www.teachya.com/grammar/intermediate/must_should_have_to.php
