شرکت در آزمون آنلاین زبان انگلیسی 1 - زبان انگلیسی 1 | آزمون شماره 10092

.Despite opposition from his family , he ............................ school and became an actor

Nowadays , our young scientists take great positions in the most famous universities and companies because of their ................................... on Nano materials.

Ciphers are easy to use and remember. A simple cipher, however, is also easy to break. In any language, some letters are used more than others. In English, “e” is the most common letter, followed by “t” and “a”. Some letters frequently occur together, such as th and ch. By studying several messages, a code breaker can easily figure out a simple cipher. Complex ciphers use a different cipher, or code, for each letter in a message. The letters in a keyword reveal which cipher is used for each letter. Only people who know the keyword can read the message. Codes can be almost unbreakable if they use combinations of ciphers and change the keyword often.

During World War II (1939-1945), math experts in Britain broke the German military codes. Britain was at war with Germany. German military forces coded messages with a device called an Enigma machine. Enigma used gears and wheels to create millions of different ciphers. But British mathematicians and code breakers figured out the cipher and uncovered German military plans.

The word “Cipher” in line 1 is closest in meaning to a/an … .