Answer:
My first is twice in apple but not once in tart. My second is in liver but not in heart. My third is in giant and also in ghost. Whole I’m best when I am roast.
Until I am measured I am not known, Yet how you miss me when I have flown.
What has four legs during the day; and six or eight during the night?
This only turns over once you have traveled very far. What is it?
Don't do this in the shallow end.
What did the piece of wood say when he saw the screwdriver and screws approaching?