There is a group of expressions using 'up' where the 'up' is not necessary. For example you can say 'fill' or 'fill up' and it means almost the same thing. So why do we add the 'up'? Well one possible answer is that 'we do it because we do it' – we have just developed the habit of adding 'up'. However, often the 'up' seems to 'intensify' the verb, to make it more 'complete'.
Look at these examples and see what I mean.
If you are late, you need to 'hurry up'.
- Please hurry up. We are terribly late.
- We need to hurry up or we will miss our flight.
You can 'ring up' somebody on the telephone.
- I will ring you up when I get back.
- You can ring me up if you need any help.
If you cut your skin, it needs to 'heal up'.
- This will take a week to heal up.
- I cut myself shaving and it will not heal up.
Before I go on a long journey, I have to 'fill up' my car with petrol ( or if I were in the US 'gas'.)
- I need to fill up my car.
- The concert filled up quickly and not everybody could get in.
When I send a package, I 'wrap it up' well.
- Could you wrap this up for me?
- They didn't wrap it up properly and it got damaged.
If you have something valuable, it is a good idea to 'lock it up'.
- He did not lock up his desk properly and somebody stole his calculator.
- I think they should lock up pedophiles for a very long time.
If you don't have enough money to buy something, you need to 'save up'.
- I am saving up to go on a trip to New York.
- You'll have to save up if you want to buy a car.
When things are in a mess, you need to 'tidy them up'.
- We need to tidy up the office before the visitor comes.
- Tidy up your desk. It's such a mess.