Lesson 5 / handout 5b - KEY

Gethin 11D, obligation/ absence of obligation

 

Fill in missing letters:

 

a)         must or mustn’t expresses  INTERNAL   OBLIGATION = a speaker’s authority over themselves, has its origin in the speaker (or writer) (esp. used in the first person): I/We really must do something about the weeds in the garden. I/We mustn’t forget!

            In other persons  (you, etc.) must conveys more strongly than have to the idea of inescapable obligation or urgency, e.g.: You must phone home at once. It’s urgent.

 

b)        have to or have got to expresses  EXTERNAL   OBLIGATION  = an external authority, has its origin in circumstance ( necessity) or in a person other than the speaker or writer: We have to/’ve got to send these forms back before the end of the month. (= we are required to do so by law)

            need to expresses a  weaker   sense of  external obligation than have to, to which it corresponds in the present and future tenses. A past   tense  (needed to) is rarely used except in the interrogative:

Did you need to…?

           

c)         must (not have to or have got to) is used in public notices or documents expressing                        COMMANDS:

Cyclists must dismount. Candidates must choose five questions.

            Must you …? is generally preferred to Do you have to…? or Have you got to…? to mean ‘Can’t you stop yourself?’

Must you always interrupt me when I’m speaking?

            must is also used in pressing  invitations, such as: You really must come and see us some time.

            Similarly, must is also used in emphatic   advice: You really must take a holiday this year.  

 

d)        ABSENCE of  INTERNAL OBLIGATION:

-  in the present or future, we use the auxiliary needn’t: You needn’t get my clothes ready now; I’ll do it later.

e)         ABSENCE  of EXTERNAL OBLIGATION:

- in the present or future, we use the non-auxiliary don’t need to/don’t have to or won’t need to/won’t have to:

I don’t need to/don’t have to leave for another eight hours. OR I haven’t got to leave …

 

f)         To express absence of obligation  in the past we use:

- didn’t need to / didn’t have to when we did not do anything because it was not necessary: Fortunately, I didn’t have to/ didn’t need to wait more than a couple of minutes for a bus yesterday.

- needn’t have when we did do something although it was not necessary: You needn’t have worried like that, because everything has turned out all right.   

 

 

References:

Gethin, H. (1992) Grammar in Context. Proficiency Level English. Harlow: Longman. – chapter 11D, pp. 129 – 132