We use SHOULD to give advice, make recommendations, and say what is right or wrong. SHOULD is a modal verb. Remember: modal verbs have special grammar rules: they have no past form, we don't use 'to' after them, and they don't change in the 3rd person (no 's').
Here are 8 example sentences with SHOULD and alternative ways to say the same thing:
1. You should see a doctor. (It's a good idea to see a doctor.)
2. She should study more for the exam. (It's important for her to study more for the exam.)
3. We shouldn't eat so much sugar. (It's bad to eat so much sugar.)
4. They should arrive early for the interview. (It's better to arrive early for the interview.)
5. You shouldn't drive when you're tired. (It's dangerous to drive when you're tired.)
6. He should apologize to his friend. (It's the right thing to apologize to his friend.)
7. You should visit that new restaurant. (I recommend visiting that new restaurant.)
8. We shouldn't waste water. (It's wrong to waste water.)
Notice how SHOULD is followed directly by the verb (see, study, eat, arrive). We don't say 'should to see' or 'should sees'. The negative form is SHOULDN'T (should not). Use SHOULD when you want to tell someone what is good, right, or the best thing to do.
