Language is sometimes written as a code so that people can communicate secrets. During     1     Second World War, the German Navy （海军）used a code to send messages. The British broke the code and     2     （learn） about many German plans. The Japanese also used a code to talk to     3     （they） ships at sea. It was called the Purple Code. Although the Americans soon broke this code, the Japanese didn’t know it     4    （break）. In 1942 , the Americans began to use their own code to send     5     （secret）. A few Navajo（纳瓦在人）Indians made this code     6    （base） on their language, which only some American Indians spoke. The code described a few things the American army did. Only they could understand this code, so they went with the army as it fought against the Japanese. These Navajo soldiers promised     7    （keep） this code a secret, even though this could cause their     8    （die）. The Japanese never broke the code because they knew nothing     9     the Navajo language. And the code,     10     connected two languages, helped win the war in the Pacific.

Who is smarter？A human being or artificial intelligence？The question     1    （sweep）across the world when a Google-developed program called AlphaGo defeated the world top player. So，what comes next？

Some people are pessimistic，saying that the full development of artificial intelligence，    2     AI in short，could mean the end of the human race. So are we really about to live in the world     3    （show）in the Terminator（终结者）movies？

“Not quite，”answered John Markoff of The New York Times，    4     is optimistic about the future. “We think that，for the human beings，things like sight and balance，    5    （be）natural and ordinary in our life. Also，we humans are better at making     6    （adjust）to the surroundings. We have a long way to go before AI can     7    （true）begin to be similar to the human brain，even though the technology can be great.” Meanwhile，John Markoff said that researchers should build artificial intelligence to make people more     8    （effect）.

“Our fate（命运）is     9     our own hands，”he added.“Since technology depends on the values of     10     (it) creators, we can choose to use technology to improve the world.”

4 . Easy Ways to Build Vocabulary

It's not all that hard to build an advanced and large vocabulary. Like many things in life, it's     1    ongoing process, and the best part of the process is that there's enough room for improvement,     2    means you'll just keep getting better and better. Of course you have to work at it. You wouldn't think that a few     3    (month) of exercise in your teens would be enough     4     the rest of your life, and that's also true for building your vocabulary--you have to keep at it daily, and pretty soon you will find that you have an excellent vocabulary.

The giant panda     1     (love) by people throughout the world. Chinese scientists     2     (recent) had a chance to study a wild female panda with a newborn baby. She was a very     3    (care) mother. For 25days, she never left her baby, not even to find something     4     (eat)! She would not let any other pandas come near. She licked the baby constantly to keep it clean. Any smell might attract natural     5    (enemy) that would try to eat the little comforting panda. The mother held the baby in her front paws much the way a human does.     6     it cried, she rocked it back and forth and gave it little comforting pats. The mother continued to care for the young panda     7     more than two years. By that time, the panda no longer needed     8    (it) mother for food. However, it stayed with her and learned about the ways of the forest. Then, after two and a half years, the mother     9     (drive) the young panda away. It was time for her to have a new baby,     10     it was also time for the young panda to be independent.