Answer:
There are 7 birds in a tree. A hunter shoots one bird down. How many birds are left in the tree?
What object has keys that open no locks, space but no room, and you can enter but not go in?
Once you know it exists, it no longer exists. What is it?
Temporary evidence of where you've been strolling
What word do all dictionaries spell wrong?
When is it bad luck to see a black cat?