'to set about' is to dealing with something in a particular way.
- I need to find a new flat but I'm not sure how to set about looking for one.
- I don't think you are setting about it the right way.
'to set against' means balance one thing against another.
- The advantages are not so big when set against the disadvantages.
- We can set our expenses against the tax.
'to be set against' something means to be opposed to doing it.
- He won't change his mind. He is absolutely set against it.
- His parents were set against him becoming a musician and made him study engineering.
'to set aside' means to use something, often time or money, for a specific purpose.
- I have enough money for the deposit set aside.
- I've set aside Monday and Tuesday to work on it.
'to set back' is to cause a delay.
- Bad weather was the reason that the launch of the rocket was set back until Monday.
- The whole project has been set back by the late delivery of some of the parts.
'to set down' something you are holding means to put it down.
- She lifted up the teapot but set it down again without pouring any tea.
- The waitress set down an enormous plate of steak and salad in front of me.
'to set down' your ideas or some facts means to record by writing them.
- Here is the leaflet where we have set down guidelines for our employees.
- We were all asked to set down our views on what had happened.
'to set in' is when something unpleasant starts and seems likely to continue.
- It looks as if the rain has set in for the afternoon.
- Panic didn't really set in until just before I was due to give my presentation.
'to set off' means to start on a journey.
- Sorry we're late. We didn't set off until half past eight.
- The weather was perfect when we set off but it was raining when we got back.