Got a bun in the oven...
as a newcomer to Britain I was invited for dinner and the friend said 'I've got a bun in the oven'- I blushed and apologised and said I was not sure I could eat rabbit. Oh they laughed.
Another French friend was married to a doctor and they ordered a fridge to put in an alcove. It fitted just right, with a few mm to spare and the chap said 'Great, just what the doctor ordered!' - she was really surprised and asked how he knew. Know what- he said 