BEIJING, June 7 (Xinhua) -- After this year's national college entrance exams, Gan Fubao will have collected all 40 exam papers since the exams resumed in 1977.

Gan, 70, from Nanchang, capital of east China's Jiangxi Province, holds a deep affection for the exam, known as the "Gaokao" in Chinese.

The exam was disrupted by the Cultural Revolution (1966-1976) and its reintroduction by then leader Deng Xiaoping was a clear signal that times had changed.

Gan started to collect the papers when he sat the exam in 1977. After completing the Gaokao, Gan was admitted to study physics at Jiangxi University, and bid farewell to his life as a factory worker. He then became an engineer after graduation.

In addition to his hobby of collecting exam papers, Gao likes pondering on the themes, especially the essay topics, which he regards as a mirror reflecting a changing China over the decades.

"Each essay topic represents the characteristics of the time," he said.

Liu Xiang, editor-in-chief of a Communist Party magazine, still remembers the essay he wrote when sitting the Gaokao in 1977.

"The topic for the essay was 'An Unforgettable Day,'" he recalled. He wrote about the downfall of the "Gang of Four", a disgraced political faction composed of four officials that came to prominence during the Cultural Revolution.

"If they had remained in power, I might be still a farmer in my village and may never have had the chance to take the college entrance exam," he said.

Liu, 59, graduated from middle school in 1975, before returning to his hometown of Zhucheng in east China's Shandong Province, where he worked first as a tractor driver and then a village teacher.

He had expected to continue on that path, until October 1977, when he heard in a news broadcast that China would resume the Gaokao system.

Liu saw an opportunity to change his fate. "I elaborated on the significance of the crushing of the Gang of Four, and expressed my joy at being able to sit such an important exam," he said.

After talking with his fellow exam takers, Liu later learned that most of them had either written about that same day, or the day when Chairman Mao died. "There is also someone who wrote about the day he got married, but he didn't get a high score," he said.

During the initial years, the essay topics students were asked to write about were highly political.

In 1977, the topic for Beijing students was "My Revolutionary Year," while for students in northeast China's Jilin Province it was "A Great Success: The Unforgettable October, 1976." The following year, the topic was "The Problem of Speed Is A Problem of Politics."

"Such topics closely reflected the era," said Li Shanfeng, chairman of the Shandong Provincial Sociological Association. "Although the Cultural Revolution was over, highly politicized topics did not go away overnight."

After the beginning of the reform and opening-up program, the economy became increasingly important and the change could also be seen in essay topics.

Ma Yanwen, a Chinese language teacher at a middle school in Shandong Province, remembered that in 1985, students were asked to write "a letter to the Guangming Daily to talk about pollution." In 1986, the topic was "Tree, Forest and Climate."

"While economic development was at the center of government work, people began to think about the environment," Ma said.

Topics became increasingly diversified in the 1990s, when the old values were challenged.

Shi Jing, a teacher at an experimental middle school in Shandong, remembered when the 1994 essay topic was "An Attempt," a student wrote about a romance at school. "At that time, teenage romance was not allowed, so the essay was initially given only 25 points," Shi said.

The essay was then passed to Professor Song Suiliang, head of the team marking the exam papers. Song liked the story. "Falling in love is one of the biggest endeavors of one's life," he noted, giving it the full 50 points available.

Greater importance was attached to students' inner thoughts and beliefs during the following years. In 2001, the essay topic was "Honesty." In 2002, it was "The Choice of the Heart," and in 2004, students in Beijing were asked to write about "Tolerance."

In recent years, the topics have become more thought-provoking and closer to life with distinct characteristics of the times.

In 2015, one topic was extracted from Weibo, a Twitter-like service, where a daughter who reported her father's illegal use of a mobile phone while driving sparked controversy.

On Wednesday morning, this year's Gaokao essay topics were unveiled. One of them was "Chose two to three keywords to help foreign youth understand China, such as Belt and Road, giant pandas, Chinese cuisine, the Great Wall, shared bikes, air pollution, high-speed rail or mobile payment." Other topics were "My Gaokao" or "The Gaokao in My Eyes," which were chosen to mark the 40 year anniversary of the resumption of the exam.

Xia Xuelan, a sociologist at Peking University, said the Gaokao essay topics have changed from larger issues to more specific topics focusing on students' daily lives and feelings.

Liu began writing about the exams twenty years ago. "The Gaokao is always improving," he said. "In spite of its imperfections, it has changed the course of our country and the fates of a myriad of people."