题干

如下数表是由从1开始的连续自然数组成,观察规律并完成各题的解答.

(1)表中第6行的最后一个数是____ ,第n行的最后一个数是____ ;

(2)若用(a,b)表示一个数在数表中的位置,如9的位置是(4,3),则168的位置是____ .

 

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答案(点此获取答案解析)

21,
n
n
+
1
2
,(18,15)

同类题3

阅读理解

    When Jeanne Calment entered the world in 1875, telephones and automobiles still lay in the future. Albert Einstein and Pablo Picasso were not yet born. The Eiffel Tower was 14 years from being built. As a teenager, she met Vincent Van Gogh, near her home in Arles, in the south of France. He was “very ugly, ungracious, impolite, sick—I forgive him, they called him loco (精神失常的)”, she recalled. When she died last week at age 122, she was the world's eldest person. (There are others who claimed to the title, but only Calment had the official documents to prove her age.)

    Each February 21, her birthday, she would share the secrets of long life. Some years it was “a sense of humour”, others it was “keeping busy”. “God must have forgotten me,” she once explained. The truth probably was that her mother reportedly lived to be 86 and her father 94.

    Her life had its sadness: she outlived her husband, her only daughter and her grandson. According to a friend, she was imperturbable. “If you can't do anything about it,” she reportedly said, “don't worry about it.”

    In her last years she was nearly blind and deaf, but her health remained good. She ate a few bars of chocolate each week and continued smoking until a few years ago, when she could no longer light her own cigarettes. She never lost her sense of humour. On her 110th birthday, she commented, “I've only ever had one wrinkle, and I'm sitting on it. “Her longevity made her famous; her spirit made her eternal (永恒的).

同类题4

阅读下列短文,从每题所给的四个选项 A、B、C、D中选出最佳选项。

B

    MSG (monosodium glutamate) is a food additive (食品添加剂), which has been widely used by many food factories all over the world since it appeared first in Japan in 1909.

    MSG is a substance that is added to some food to improve its original (原先的) taste and colour. It is used in foods around the world such as cakes, bread, frozen meats, fish and vegetables. In the beginning, people thought MSG was safe just like salt and sugar. However, in 1968 some people reported they seemed to have bad reactions (反应) to MSG after having had a meal at a restaurant. They included headaches and quick heartbeat (心跳). It was also reported that MSG excited a person's brain and caused his death in Japan. Scientists think that MSG may lead to many neurological disorders (神经紊乱). In mice studies done by a university, the evidence showed the mice didn't want to eat the food including MSG.

    Today many food companies "hide" MSG on food labels (标签) by using different names. If you see "natural flavorings", "hydrolyzed protein" and "spices" in a food label, you are probably seeing a hidden way to "report" MSG in a food label. Every time we have a meal in a restaurant, we always feel the food very delicious to taste, but sometimes it is dangerous for our health because some poisonous food additives have been added to the food.

    To protect people's health, our governments, from central to local, are taking actions to stop factories producing poisonous food additives.