Have to for obligation and need to for necessity

Modal Verbs of Obligation and Necessity


1. Use of Modal Verbs of Obligation and Necessity

Modal Verbs can be used to talk about obligation, freedom and necessity to do something. We use the following modal verbs:
Must, Have to, Need to, Don’t have to, Needn’t, Don’t Need to + infinitive

2. Talking about Obligation and Necessity in the present

2.1 Obligation

Have to and must are both used to express obligation. There is a slight difference between the way they are used.
Have to shows us that the obligation comes from somebody else. It’s a law or a rule and the speaker can’t change it.
  • In Britain you have to wear a seat belt when you drive
Must shows us that the obligation comes from the speaker. It isn’t a law or a rule.
  • I must finish this before I go home
Sometimes if the speaker agrees with an external rule they will use must
  • In Britain you must wear a seat belt when you drive.
Need to have to and need to are often used in the same context, but many times, need to is used to express something that is less urgent, something in which you have a choice.
  • I have to work late tonight
  • I need to work late tonight

2.2 Forbidden

If something is forbidden must not / mustn’t + base form of the verb
  • You must not drive drink and drive.
  • You mustn’t leave medicines where children can find them.

2.3 No obligation

We use don’t have to to show that there is no obligation. You can do something if you want to but it’s not compulsory. 
don’t /doesn’t /didn’t + have to + base form of the verb
  • You don’t have to wear a tie in our office. You can wear a tie if you want to but it’s OK if you don’t.
needn’t + base form of the verb
  • You needn’t worry about me. I’ll be fine.

3.Talking about Obligation and Necessity in the past

There is no past form of must so we use had to
had to / needed to + base form of the verb
  1. I had to work late last night.
  2. I needed to drink a few cups of coffee in order to stay awake.
Note: have to and need to are often used in the same context, but many times, need to is used to express something that is less urgent, something in which you have a choice.

3.Talking about Obligation and Necessity in the future

There is no future form of must so we use have to
will have to / will need to + infinitive
  • I will have to work late last night.
  • I will need to drink a few cups of coffee in order to stay awake.

Resultado de imagen para have to for obligation and need to for necessity



https://www.youtube.com/watch?v=fm2m4CHEWnc

Comentarios

Publicar un comentario

Entradas más populares de este blog

superlativo

Imagen
We use a superlative to say that a thing or person is the most of a group. When we use a superlative adjective ('the tallest student') before the noun, we generally use it with 'the'. This is because there's only one (or one group) of the thing we are talking about. There is one student who is the tallest in the class, and because it's clear to the listener which one we mean, we usually use 'the': She's  the  most beautiful girl I've ever seen. It's  the  best café in London. John and Lisa are  the  most intelligent students here. This bowl is  the  biggest one. Remember, we don't use 'the' when there is a possessive: He's my best student. That's our most important goal. It's possible to drop 'the' when the adjective is used later in the sentence, rather than directly before the noun. We can choose either 'the' or 'no article', with no change in meaning: She is (the) most beautiful
Leer más