Kinds of modals and their use in English sentences:
|1.||CAN||AbilityPermission||I can do the test.All students can enter the room|
|2.||COULD||Past abilityPolite questions||We could be in love.Could I have your name?|
|3.||MAY||PermissionPossibility||May I enter the room?They may be late.||They may have been here yesterday.|
|4.||MIGHT||possibility||She might come tonight|
|5.||SHOULD/OUGHT TO||Advisabilityexpectation||You should study hard.My mother should pick me up soon.|
|6.||HAD BETTER||Strong advisability||You had better be on time or we will go without you.|
|7.||MUST||Necessityconclusion||I must go now.She is not here, she must be absent today.|
|8.||HAVE TO||necessity||I have to see him.|
|9.||HAVE GOT TO||necessity||I have got to go|
|10||WILL||Simple futurePolite request||I will study English tonight.Will you close your book?|
|11||WOULD||Polite requestPreferenceconditional||Would you mind opening the door?I would rather to go by car.If I found money, I would keep it.|
|12||SHALL||Simple future(I and we)Polite questions (suggestion)||I shall arrive there tomorrow.Shall I make you a cup of tea?|
“Should‘ (do) is used to say what we think is a good thing to do or the right thing to do (to give opinion about something). We often use should when we ask for or give an opinion about something.
- I don’t think you should work so hard.
- The government should do something about the economy.
- You’ve been coughing a lot. You shouldn’t smoke so much.
‘Should’ is also to say something is not right or not we expect.
- Those children shouldn’t be playing. They should be at school.
For the past, we use ‘should have’ (done) to say that someone did the wrong thing:
- She’s feeling sick. She shouldn’t have eaten so much chocolate.
- Why were you at home yesterday? You should have been at school.