I like coffee, maybe a little too much. I think I should cut down on coffee. My dad used to say that for a healthy life, you should eat and drink in moderation. In other words, you shouldn’t have too much of any one thing. I should have listened to his advice. What do you think I should do? Do you think I must follow my doctor’s advice?
Today we will look at how to use should and must. Do you know how to use these words? Take a look at the paragraph above and then check out today’s lesson:
Should is an auxiliary verb and usually comes before the main verb in the sentence. Should is used to show obligation. Must is also an auxiliary verb, but it is much stronger than should and is often used for orders.
Compare the following sentences:
- My doctor said that I should cut down on coffee. My doctor gave me a strong suggestion.
- My doctor said that I must cut down on coffee. My doctor gave me an order.
- You shouldn’t use a cell phone on the train. This shows your obligation not to use the phone.
- You mustn’t use a cell phone on the train. Maybe there is a regulation prohibiting cell phone use.
- You shouldn’t smoke in public places in New York. Not smoking in public is a social obligation
- You mustn’t smoke in public places in New York. Smoking in public is prohibited by law.
Should is used to show probability, but must is not used this way:
- The meeting should be finished by 2:00. Not, the meeting must be finished…
- The flight should arrive on time. Not, the flight must arrive…
Must is used to show something is sure or certain.
- The train must be running late. I’m sure the train is running late
- You worked until 10 last night! You must be tired. I’m sure you are tired.
Should is used with the past participle (pp) to show what was supposed to happen, but it didn’t:
- The meeting should have finished by 2:00. But, the meeting didn’t finish by 2:00.
- I should have called before I left the house. But I didn’t call before I left the house.
Must is also used with the past participle (pp) when we want to show certainty about the past
- The meeting must have finished by 2:00. I’m sure it finished by 2:00.
- I must have left my wallet at home. I’m sure I left my wallet at home.
Well, I should stop for today. You must be tired from studying so hard. I hope you enjoyed today’s lesson…see you next time!