This is VOA. The National Cryptologic Museum is on Fort George G. Meade, a military base near Washington, DC. The method of hiding exact meanings is called coding. People have used secret codes throughout history to protect important information. The National Cryptologic Museum celebrated 60 years of cryptologic excellence in 2012. One event there marked the sixtieth anniversary of the National Security Agency. Two former NSA workers shared their memories of operating a code machine called Sigaba. In 1940, an American woman named Genevieve Grotjan found some information being repeated in Japanese coded messages. Her discovery helped the United States understand secret Japanese diplomatic messages. After the United States understood the code, it was possible to study messages from the Japanese ambassador to Germany and to his supervisors in Japan. Understanding these messages helped the United States prepare for a possible war in the Pacific with Japan. After the attack on Pearl Harbor. the American naval commander in the Pacific Ocean was Chester Nimitz. His forces were much smaller than the Japanese Naval forces. And the Japanese had been winning many victories. Joseph Rochefort had worked for several months to read the secret Japanese Naval code called JN-25. If he could understand enough of the code, he would be able to give Admiral Nimitz very valuable information. From the beginning of 1942, the Japanese code discussed a place called "AF." Joseph Rochefort felt the Japanese were planning an important battle aimed at "AF." After several weeks, he and other naval experts told Admiral Nimitz that their best idea was that the "AF" in the Japanese code was the American-held island of Midway. Admiral Nimitz said he must have more information to prepare for such an attack. The Navy experts decided to trick Japan. They told the American military force on Midway to broadcast a false message. The message would say the island was having problems with its water-processing equipment. The message asked that fresh... The Americans used the Navajo language in their coding system during the Second World War for the reason that _ . A) unusual language was successfully used for codes B) it was commonly used in coding system worldwide C) the United States Marine Corps invented it then D) it was the most beautiful language in the world
A
(Question)
Speeding off in a stolen car, the thief thinks he has got a great catch.But he is in for an unwelcome surprise.The car is fitted with a remote immobilizer, and a radio signal from a control centre miles away will ensure that once the thief switches the engine off, he will not be able to start it again. The idea goes like this.A control box fitted to the car contains a mini-cellphone, a micro-processor and memory, and a GPS satellite positioning receiver.If the car is stolen, a coded cellphone signal will tell the control centre to block the vehicle's engine management system and prevent the engine being restarted. In the UK, a set of technical fixes is already making life harder for car thieves." ," says Martyn Randall, a security expert.He says it would only take him a few minutes to teach a person how to steal a car, using a bare minimum of tools.But only if the car is more than 10 years old. Modern cars are far tougher to steal, as their engine management computer won't allow them to start unless they receive a unique ID code sent out by the ignition key.In the UK, technologies like this have helped achieve a 31% drop in vehicle-related crime since 1997. But determined criminals are still managing to find other ways to steal cars, often by getting hold of the owner's keys.And key theft is responsible for 40% of the thefts of vehicles fitted with a tracking system. If the car travels 100 metres without the driver confirming their ID, the system will send a signal to an operations centre that it has been stolen.The hundred metres minimum avoids false alarms due to inaccuracies in the GPS signal. Staff at the centre will then contact the owner to confirm that the car really is missing, and keep police informed of the vehicle's movements via the car's GPS unit. The remote immobilizer is fitted to a car to _ . A) prevent car theft by sending a radio signal to the car owner B) help the police make a surprise attack on the car thief C) prevent the car thief from restarting it once it stops D) allow the car to lock automatically when stolen
(Answer)
C
Question: Top 10 Best-Sellers for $10 ( regularly between $15.95-$19.95) Based on October's sales, our customers have chosen our 10 bestselling books and today we are placing these top 10 bestsellers on sale for $10 each! Heart of a Caregiver is a book in praise of all the unknown heroes who provide loving care for others each day -- nurses, hospital workers, the CNAs and so on. It's the only book of its kind on the market that is devoted to thanking caregivers. We all know caregivers who have touched our lives. This book makes a beautiful gift to thank them for the beautiful work they do. Regularly priced at $15.95, today it's only $10. Friends, the family we choose for ourselves is a book that you'll want to read and more importantly, one you'll want to share with all of your friends, to thank them for their gifts of time, encouragement and support. This heartwarming book makes a great gift for Christmas or for any time! Regularly priced at $15.95, today it's only $10. The Richest Man in Town is certain to make you laugh, cry and think about life. It's a true story that describes the important things in life in an unforgettable way. It is a beautifully written, heartwarming story about an amazing man who touched so many people in a special way. Marty was a simple man who ran a cash register in a Wal-Mart store in South Dakota. He worked hard and was good to people. Can it be so simple? It's a meaningful story to share with friends, family and all employees. They will love it, and love you for giving it. Regularly priced at $19.95, today it's only $10. Now that we have given you a preview of our top 10 list, click here to see all top 10 books available today only for $10 each! Make sure to share this email with your friends and family so they can enjoy the savings too! Sale ends tonight, Thursday 11/03/2011 at 11:59 pm CST . The advertisement may be found _ . A) in a newspaper B) in a magazine C) on TV D) on the Internet
Answer:
D