$1.\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_(1941-2010)$ was best known for his work at Bletchley Park during World War II$,$ helping to break the German Enigma code that was used to encrypt messages during WWII

$2.$ In the $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ called $"\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_,"$ the computer has to pass for a human after answering questions right more than $30\%$ of the time during a $5-$minute conversation.

$3.$ A $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ is used to determine if the computer is a person or a computer

$4.$ A $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ is used to determine if the user is a human by typing in letters or selecting objects in a picture.