Helen: You posted your house-keys? Let me guess, you dropped them in the letterbox by mistake.
Neil: Yes, I got mixed up. Instead of putting a letter in, I put my keys in.
Helen: Oh dear.
Neil: But I have my address attached to my keys, so maybe they'll end up getting posted back to me.
Helen: Yes, you might get them posted back to your house or you might get burgled, now that someone has your address as well as your house-keys.
Neil: Oh no, thieves might get into my house! I'd better go and wait outside to see what happens.
Helen: OK, good luck.
Neil: I'll keep you posted. See you later!
Helen: Neil will 'keep me posted'. That doesn't mean he's going to put me in the postbox – even though he's obviously a bit confused about what should or shouldn't go in postboxes! It means he will keep me informed, he will tell me what happens. Listen to some examples:
I don't know what time they're arriving, but I'll keep you posted! Keep me posted on how things go in your new job! I kept them posted on what was happening.
Helen: I hope Neil's keys find their way home. Hello?
Neil: Hi, it's Neil.
Helen: Neil! Any news?
Neil: Well, someone posted my keys back to me.
Helen: Great!
Neil: But they put them through the letterbox!
Helen: Oh no, so you've got your keys back, but now you're locked out!
Neil: And I'm stuck! I tried to get through a window but I don't fit. I'm half-in, half-out. Thank goodness, help must be arriving.
Police: Don't move!
Neil: Does it look like I can move?
Police: Hands on your head!
Helen: Oh dear, it sounds like someone called the police – they probably thought Neil was a burglar.
Neil: But, this is my house!
Police: Is it indeed?
Helen: I'd better leave you to explain yourself now. But do keep me posted Neil!
Neil: Keep you posted! How am I going to do that if I'm locked up? Arrested for for breaking into my own house!