I have never seen Hawk-Eye technology to be used on clay tournaments. French Open is running at the moment and it is not being used there. What are the reasons for not using this technology on clay? Do tennis federations have some rules against it?

Do the reciever need to wait for the ball to bounce on the table , before hitting it back to the opponent, to both singles and doubles

Pitcher A allows the potential lead runner to reach base in a tie game. Pitcher B comes in to relieve and gives up a hit, then gets the lead runner out on a fielder's choice. Now, pitcher A has nobody left he put on base. Pitcher B gives up a run-scoring hit and the batted Pitcher B put on with a...