Good Riddles

Question: A man wants to have a party in thirty-one days where he will be serving his 1000 barrels of wine. The only problem is that one of his enemies poisoned one of the barrels. The poison kills any man who drinks any of the wine in about 30 days, give or take a few hours. The man has 10 plants that are also killed by the poison in 30 days and can be used to test the wine. How can identify the single poisoned barrel of wine?

Question: A man has hundreds of bodies buried on his land, many of which are cops and criminals. Many people find out what he has been doing, but none go to the police.

Why not?

Question: It's got twists and turns, but has no curves.
Twist it to fix it, turn it to ruin it.

What is it?

Question: If you're in 3rd place and you passed the person in 2nd, what place are you in?

Question: Change a long pause into a short one by doubling a letter.What are the words?