【简答题】Talking with people is necessary in our daily activities and it is also very important. However, we all have different styles of communicating. Some people seem to be liked by most of the people while...
【单选题】“bridge out” wouldactually mean “Meet me.” 40 However, it is also hard to keep a code booksecret for long. So codes must be changed frequently.
A.
It is very hard to break a code without the code book.
B.
In any language, some letters are used more than others.
C.
Only people who know the keyword can read the message.
D.
As long as there have been codes, people have tried to break them.
G.
You can hide a message by having the first letters of each word spell it out. F. With a code book, you might write down words that would stand for other words. G. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.F. G.