how use should and must

##Must We use must in three main ways: * to talk about something that has to be done because it’s compulsory or obligatory (that is, it’s absolutely necessary to obey a rule, law, order, or instruction): :-Online stores must give a cooling-off period of seven working days. :-She was told that she must not discuss the case with third parties, including her MP. *or because it’s very important: :-To calm public opinion, police must quickly arrest the culprits and solve this case. :-I must get back to work: a deadline approaches. *to express the view that something is highly likely because it’s a logical conclusion based on something else that the speaker knows, or it’s the normal thing to expect: :-Our measurements show that exactly the opposite must be the case. :-Her mega hairdo must have taken several cans of hairspray to achieve. *to say to someone that you strongly recommend or advise something because it’s a good idea: :-If you go to Barcelona, you must see the cathedral. :-We get on well and keep saying we must meet up for lunch sometime. ##Should Here are the three main meanings of should: * to talk about what we think is the right or correct thing to do, especially from the point of view of duty or appropriateness: :-All employees should be provided with a proper job description. :-Children shouldn’t be allowed to watch too much TV. *to give or ask for advice or suggestions: :-I told Kathy she should try to get some rest. :-Can you recommend any exercises, or should I see a doctor? *to predict that something will probably happen or is expected to be the case, based on logic or a typical situation: :-My sister’s on her way, she should be here soon. :-By next month I should have enough money to buy a car.