We use should, It’s a good idea … and Why don’t you …? to give advice. We can also use ought to, but it is less common.
– You don’t look well. You should stay at home today.
– It’s a good idea to have a big breakfast.
– You ought to write new vocabulary in a notebook.
We can use should in the negative. We can make it stronger by adding certainly.
– You shouldn’t eat so much – it’s not good for you.
– You certainly shouldn’t eat so much sugar and fried food.
We can use must or really must to give stronger (positive) advice.
– You must tell me if there’s a problem.
– You really must see a doctor.
We don’t usually use ought to in the negative. We can use it with I don’t think …
– You oughtn’t to invite so many people. X
– I don’t think you ought to invite so many people.
We can use should have and shouldn’t have to criticise our own or someone else’s past behaviour.
– You should have worn much smarter clothes for the interview.
– You shouldn’t have said such horrible things to Carla.
We can use intensifiers to make the meaning of adjectives stronger.
Gradable adjectives are words like good, big and clever. (They have a comparative form.)
We can ue the intensifiers very, really and extremely to make the meaning stronger.
– The concert was extremely good.
– They’re building a very big supermarket on the edge of the town.
– He’s really clever but he dosen’t study enough.
Non gradable adjectives are often extreme words like fantastic, huge and brilliant.
We can use the intensifiers really and absolutely with these.
– I’ve just read an absolutely fantastic book.
– There’s a really huge tree at the bottom of my garden.
– I think she’s an absolutely brilliant actress.