CHAPTER 11: MUST MUST VS. SHOULD MUST VS. DON'T HAVE TO

MUST
(S.B. p.p. 108-109        WB p.p. 104-106)


  • The modal must expresses obligation or necessity. This modal must is an auxiliary verb that combines with the base form of the verb. It doesn't contract with subject pronouns.
          Ex:            I must eat fewer cookies.
                            You must eat less bread.
                            She must eat more lean meat.
                            He must eat fewer eggs.



    MUSTN'T
    (S.B. p.111        W.B.p.p 107-108)


    • The affirmative forms of have to and must both express a strong obligation to do something. The negative form of have to expresses no obligation to do something.
           Ex:         I don't have to stop eating ice cream.(I can still eat ice cream)
                         He doesn´t have to stop eating cookies. (he can still east cookies)
    • The negative form of must expresses the strong obligation not to do something. Must contracts with not.
            
    Ex:        I mustn't eat as much ice cream as I did before.
                         (I can't eat as much ice cream as I did before).

                         He mustn't eat as many cookies as he did before.
                         (He can't eat as many as he did before)
    • Some verbs, such as stop, are commonly followed by gerunds. (see level 3 english blog  ch. 7 verb + infinitive/gerund)
            Ex:         Do you have to stop eating candy?
                          She doesn't have to stop eating butter?


    Using Must in Present, Past, and Future

    Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how must behaves in different contexts.



    REMEMBER: Must not vs. Do not have to
    Must not suggests that you are prohibited from doing something. "Do not have to" suggests that someone is not required to do something.
    Examples:
    • You must not eat that. It is forbidden, it is not allowed.
    • You don't have to eat that. You can if you want to, but it is not necessary
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    LET'S PLAY A GAME CALLED "FOOD CONFESSIONS"


    candy                                           potatoes                             soda
    fruit                                             vegetables                          milk

    french fries                                  fatty meat                           salt
    carrots                                         fish                                     pepper

    rich desserts                                chocolate cake                      butter
    apples and oranges                       pears and grapes                    margarine

    salt                                               chocolate cake                    cookies
    pepper                                         oranges                                yogurt

    Confession (example): I always eat too much candy. My doctor says I must eat less candy and more fruit.
    Note: You can use any other food item you wish!

    MUST VS DON'T HAVE TO

    • Have to and must are used to indicate a rule or an obligation. They have almost the same meaning.
    • Have to is often used to indicate the obligation comes from outside.
          Ex:  I have to lose weight (the doctor told me).
    • Must often shows an internal feeling,
           Ex:  I must call my mother tonight.


    • Don't have to and must not (mustn't) are very different.
           Don't have to shows a lack of obligation / no rule
            Ex: You don't have to carry your umbrella when it rains.
                (but you can if you want to)
            
            Mustn't indicates prohibition, the existence of a rule saying don't.
            Ex: You mustn't chew gum in class
                 (if you do there will be some consequence).


    • Can shows permission, that something is possible or allowed.
           Ex: People in England can drink alcohol when they're 18.

     


    Complete the following with have to, don’t have to or mustn't.
    You _________________ have a licence to drive a car.
    You _________________ have a licence to ride a bicycle.
    You _________________ tip waiters and taxi drivers in Japan.
    You _________________ wear shoes inside your house in Japan.
    Students _______________ go to school on Saturday in Japan.
    Students _______________ go to school on Saturday in England.
    Foreigners ______________ carry an ID card in Japan.
    Policemen ______________ wear a uniform.
    Passengers ________________ smoke on the subway.
    Gardeners _______________ wear ties.


    LET'S DO SOME EXERCISES:
    http://www.better-english.com/grammar/mustnt.htm
    
    LET'S WATCH THIS VIDEO:



    MUST VS. SHOULD
    (SB p.112      WB p.109)


    • We use should to suggest something.  "It is advisable to..."   The modal should expresses opinion, one person's point of view.
           Ex:     We should protect our environment. It makes good sense.  
                    We should select cars that are more fuel-efficient.
                    We should use re-usable bags when shopping.


    • We use must to express a stronger point of view"We need to..."  "We have to..." The modal must also expresses opinion, one person's point of view.
           Ex:   We must protect our environment, or our resources will disappear.
                         The car industry must change engines that burn fossil fuels.

    EXERCISES: http://www.esl-classroom.com/grammar/shouldandmust1.html

                 DO THESE EXERCISES




                     CHAPTER SUMMARY VIDEO