1. put your back into something
meaning: to use a lot of physical effort to try to do something
ex1: You could dig this plot in an afternoon if you put your back into it.
ex2: This week, what activity or task have you put your back into?
2. get sb off your back (informal)
meaning: to stop someone trying to force you to do something, or to stop someone criticizing you
ex1: I had to sell my house to get the creditors off my back.
ex2: Can you easily get beggars off your back?
3. a pat on the back
meaning: if you give someone a pat on the back, you praise them for something good that they have done
ex1: She deserves a pat on the back for keeping things going while you were away.
ex2: What have you done this week that you think deserves a pat in the back?
4. behind sb's back
meaning: if you do something behind someone's back, you do it without them knowing, in a way which is unfair
ex1: She was accused of going behind her colleagues' backs to talk to management.
ex2: What do you think are the common outcomes of talking behind someone's back?
5. You scratch my back and I'll scratch yours
meaning: something that you say to tell someone that you will help them if they will help you
ex1: I do have some information you might be interested in, but what can you offer me in return? You scratch my back and I'll scratch yours.
ex2: Why do you think people offer to another person for something in return?
6. turn sb's back on sth
meaning: to stop doing sth.
ex1: I used to go out to nightclubs every night but I turned my back on all that when I started working for this company
ex2: Have you ever turn your back onto sth before?
7. at/in the back of your mind
meaning: If something is at/in the back of your mind, you intend to do it, but are not actively thinking about it:
ex1: It's been at the back of my mind to call José for several days now, but I haven't got round to it yet.
ex2: What can't you stop thinking about these days?
8. know sth like the back of your hand (INFORMAL)
meaning: to have very good and detailed knowledge of something:
ex1: I know this area like the back of my hand.
ex2: What topic do you know like the back of your hand?
9. take a back seat
meaning: to choose not to be in a position of responsibility in an organization or activity
ex1: I don't have the time to do much on this so I suggest I take a back seat and you drive it forward.
ex2: In your team at the company, who do you think usual takes the back seat?
10. back to basics
meaning: you start to give your attention to the simplest and most important matters after ignoring them for a while:
ex1: This is all part of a new back-to-basics campaign to raise standards.
ex2: Why is it important to always go back to the basics when solving a problem?
